404pages Blog!

404!

2008-07-10T06:20:00.000-07:00

http://www.cnbeta.com/articles/59927.htm

....404!
404错误是指在服务器找不到指定的页面。404错误页面是可以自定义的。
之前为大家介绍了15个有创意的404错误页面，但您肯定看不过瘾，今天选出了hongkiat更棒的49个(部分重复)，一起来欣赏下。资源收集自Pingdom, Smashing Magazine, CNN, 404errorpages。

Today found this page!

2008-07-10T03:26:00.000-07:00

Today found this page!

Creating an Error 404 Page In WordPress Blog

2008-06-28T01:56:00.000-07:00

Creating an Error 404 Page

From WordPress Chinese

Jump to: navigation, search

While you work hard to make sure that every link actually goes to a specific web page on your site, there is always a chance that a link clicked will slam dunk and become a famous 404 ERROR PAGE NOT FOUND.

All is not lost. If your visitors encounter an error, why not be a helpful WordPress site administrator and present them with a message more useful than "NOT FOUND".

This lesson will teach you how to edit your "error" and "page not found" messages so they are more helpful to your visitors. We'll also show how to ensure your web server displays your helpful custom messages. Finally, we'll go over how to create a custom error page consistent with your Theme's style.

An Ounce of Prevention

Some errors are avoidable, you should regularly check and double check all your links. Also, if you are deleting a popular but out-of-date post, consider deleting the body of the post, and replacing it with a link referring visitors to the new page.

[编辑]

Understanding Web Error Handling

Visitors encounter errors at even the best web sites. As site administrator, you may delete out-of-date posts, but another web site may have a link to your inside page for that post.

When a user clicks on a link to a missing page, the web server will send the user an error message such as 404 Not Found. Unless your webmaster has already written custom error messages, the standard message will be in plain text and that leaves the users feeling a bit lost.

Most users are quite capable of hitting the back key, but then you've lost a visitor who may not care to waste their time hunting for the information. So as not to lose that visitor, at the very least, you'll want your custom message to provide a link to your home page.

The friendly way to handle errors is to acknowledge the error and help them find their way. This involves creating a custom Error Page or editing the one that came with your WordPress Theme.

[编辑]

Editing an Error 404 Page

The default WordPress theme has a 404.php file, but not all Themes have their own custom 404 error template file. If they do, it will be named 404.php. WordPress will automatically use that page if a Page Not Found error occurs.

The normal 404.php page shipped with your Theme will work, but does it say what you want it to say, and does it offer the kind of help you want it to offer? If the answer is no, you will want to customize the message in the template file.

To edit your Theme's 404 error template file:

Open your WordPress admin panel:
Choose Presentation menu.
Choose the Theme Editor page.
Check to see if your theme includes a '404 Template' in the list of files.
Click the link for '404 template' along the right side of the page.
Edit the message text to say what you want it to say.
Save your changes. (If the template file is not writable, see Changing File Permissions.)

While you are examining and editing your 404 template file, take a look at the simple structure of the default 404.php file. It basically features tags that display the header, sidebar, and footer, and also an area for your message:



  

    Error 404 - Not Found

So, to change the error message your visitor sees, revise the text within the h2 heading and if necessary, add more paragraphs below that.

[编辑]

Creating an Error 404 Page

If your WordPress Theme does not include a template file named 404.php, you can create your own.

Because every theme is different, there is no guarantee that copying over the 404.php template file found in the WordPress Default Theme will work, but it's a good place to start. The error page you copy from the Default Theme will adopt the style of the current theme because it actually calls the header and footer of the current theme. That's less work for you, and you may only have to edit the message to suit your particular needs.

To use the 404.php template file from the WordPress Default Theme:

Copy the file /wp-content/themes/default/404.php into the directory of your current theme.
Then, as described in the previous section, edit the error message to present your desired error message.

If copying the default 404.php into your theme directory does not work well with your theme, you have some other choices:

Change the Default Theme's 404.php template file's header, sidebar, footer, and other codes to match the rest of the Theme's layout.

Copy the index.php file of your current theme to a file called 404.php.
Open that file and delete all sections dealing with posts or comments, see The Loop.
Then, edit your 404 error message.

[编辑]

Advanced 404.php Example

This is an example of some of the technical capabilities of WordPress 404.php and HTTP Status Code Handling. You should strive to make your 404 error pages as helpful to your site visitors as you can, and when possible you should redirect broken URI's to the correct resource.

Heres an advanced 404.php that shows how to handle other types of error status codes that may be handled by your 404.php template file. This code illustrates the use of the $_SERVER['REDIRECT_STATUS'] variable common to all cgi. This may help determine the type of error so that you can provide the correct response, you don't want to waste bandwidth and CPU by serving a default 404.php page for non-404 errors.

if(!isset($_REQUEST['error']))  $AA_STATUS_CODE = '404';

else  $AA_STATUS_CODE = $_REQUEST['error'];

if(isset($_SERVER['REDIRECT_STATUS']) && $_SERVER['REDIRECT_STATUS']!='200') $AA_STATUS_CODE = $_SERVER['REDIRECT_STATUS'];

// 02-05-08 by AskApache.com



$ASKAPACHE_STATUS_CODES = array(

'400'=>array('Bad Request', 'Your browser sent a request that this server could not understand.'),

'401'=>array('Authorization Required', 'This server could not verify that you are authorized to access the document requested. Either you supplied the wrong credentials (e.g., bad password), or your browser doesn\'t understand how to supply the credentials required.'),

'402'=>array('Payment Required', 'INTERROR'),

'403'=>array('Forbidden', 'You don\'t have permission to access THEREQUESTURI on this server.'),

'404'=>array('Not Found', 'We couldn\'t find that uri on our server, though it\'s most certainly not your fault.'),

'405'=>array('Method Not Allowed', 'The requested method THEREQMETH is not allowed for the URL THEREQUESTURI.'),

'406'=>array('Not Acceptable', 'An appropriate representation of the requested resource THEREQUESTURI could not be found on this server.'),

'407'=>array('Proxy Authentication Required', 'This server could not verify that you are authorized to access the document requested. Either you supplied the wrong credentials (e.g., bad password), or your browser doesn\'t understand how to supply the credentials required.'),

'408'=>array('Request Time-out', 'Server timeout waiting for the HTTP request from the client.'),

'409'=>array('Conflict', 'INTERROR'),

'410'=>array('Gone', 'The requested resourceTHEREQUESTURIis no longer available on this server and there is no forwarding address. Please remove all references to this resource.'),

'411'=>array('Length Required', 'A request of the requested method GET requires a valid Content-length.'),

'412'=>array('Precondition Failed', 'The precondition on the request for the URL THEREQUESTURI evaluated to false.'),

'413'=>array('Request Entity Too Large', 'The requested resource THEREQUESTURI does not allow request data with GET requests, or the amount of data provided in the request exceeds the capacity limit.'),

'414'=>array('Request-URI Too Large', 'The requested URL\'s length exceeds the capacity limit for this server.'),

'415'=>array('Unsupported Media Type', 'The supplied request data is not in a format acceptable for processing by this resource.'),

'416'=>array('Requested Range Not Satisfiable', ''),

'417'=>array('Expectation Failed', 'The expectation given in the Expect request-header field could not be met by this server. The client sent Expect:'),

'422'=>array('Unprocessable Entity', 'The server understands the media type of the request entity, but was unable to process the contained instructions.'),

'423'=>array('Locked', 'The requested resource is currently locked. The lock must be released or proper identification given before the method can be applied.'),

'424'=>array('Failed Dependency', 'The method could not be performed on the resource because the requested action depended on another action and that other action failed.'),

'425'=>array('No code', 'INTERROR'),

'426'=>array('Upgrade Required', 'The requested resource can only be retrieved using SSL. The server is willing to upgrade the current connection to SSL, but your client doesn\'t support it. Either upgrade your client, or try requesting the page using https://'),

'500'=>array('Internal Server Error', 'INTERROR'),

'501'=>array('Method Not Implemented', 'GET to THEREQUESTURI not supported.'),

'502'=>array('Bad Gateway', 'The proxy server received an invalid response from an upstream server.'),

'503'=>array('Service Temporarily Unavailable', 'The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.'),

'504'=>array('Gateway Time-out', 'The proxy server did not receive a timely response from the upstream server.'),

'505'=>array('HTTP Version Not Supported', 'INTERROR'),

'506'=>array('Variant Also Negotiates', 'A variant for the requested resource THEREQUESTURI is itself a negotiable resource. This indicates a configuration error.'),

'507'=>array('Insufficient Storage', 'The method could not be performed on the resource because the server is unable to store the representation needed to successfully complete the request. There is insufficient free space left in your storage allocation.'),

'510'=>array('Not Extended', 'A mandatory extension policy in the request is not accepted by the server for this resource.')

);



function aa_print_html ($AA_C){

   global $AA_REQUEST_METHOD, $AA_REASON_PHRASE, $AA_MESSAGE;

  

   if($AA_C == '400'||$AA_C == '403'||$AA_C == '405'||$AA_C[0] == '5'){

       @header("Connection: close",1);

      

       if($AA_C=='405')@header('Allow: GET,HEAD,POST,OPTIONS,TRACE');

      

       echo "\n";

       echo "$AA_C $AA_REASON_PHRASE";

       echo "$AA_REASON_PHRASE
\n$AA_MESSAGE
\n\n";

       return true;

   } else return false;

}



if(!isset($_REQUEST['error']))  $AA_STATUS_CODE = '404';

else  $AA_STATUS_CODE = $_REQUEST['error'];

if(isset($_SERVER['REDIRECT_STATUS']) && $_SERVER['REDIRECT_STATUS']!='200') $AA_STATUS_CODE = $_SERVER['REDIRECT_STATUS'];



$AA_REQUEST_METHOD = $_SERVER['REQUEST_METHOD'];

$AA_THE_REQUEST = htmlentities(strip_tags($_SERVER['REQUEST_URI']));

$AA_REASON_PHRASE = $ASKAPACHE_STATUS_CODES[$AA_STATUS_CODE][0];

$AA_M_SR=array(array('INTERROR','THEREQUESTURI','THEREQMETH'),

array('The server encountered an internal error or misconfiguration and was unable to complete your request.',$AA_THE_REQUEST,$AA_REQUEST_METHOD));

$AA_MESSAGE  = str_replace($AA_M_SR[0],$AA_M_SR[1],$ASKAPACHE_STATUS_CODES[$AA_STATUS_CODE][1]);



ob_start();

@header("HTTP/1.1 $AA_STATUS_CODE $AA_REASON_PHRASE",1);

@header("Status: $AA_STATUS_CODE $AA_REASON_PHRASE",1);



if(!aa_print_html($AA_STATUS_CODE)){

   ?>

   

   

   

   

   

   

   

   

   

exit;

exit();

?>

[编辑]

Tips for Error Pages

There are various improvements you can make to your 404 Error web pages so let's look at some of your options.

[编辑]

Sending Proper Headers

By default, WordPress continues to send 404 pages as if they were fine. To make search engines like Google spider these pages correctly, you can add this line to the top of your theme's 404.php file.

You may have to add this before the above code in some cases.

[编辑]

Writing Friendly Messages

When an error message is displayed, you can say many things to help a visitor feel reassured they've only encountered a minor glitch, and you're doing the best you can to help them find the information they want. You can say something clever like:

"Oops, I screwed up and you discovered my fatal flaw.

Well, we're not all perfect, but we try.  Can you try this

again or maybe visit our title="Our Site" href="http://example.com/index.php">Home

Page to start fresh.  We'll do better next time."

You should also attempt to show the user what they want. Check out the AskApache Google 404 Plugin to add google search results to your 404.php

Or, say something shorter and sweeter. Almost anything you say is better than 404 Error Page Not Found. You can find more information about writing 404 Error pages on the Internet, like List Apart's Perfect 404.

As an implementation of the Perfect 404 page, this solution will tell the user it's not their fault, if it isn't and email the webmaster, according to WordPress's database. Helpful 404 page

When a visitor gets a 404 error page, it can be intimidating, and unhelpful. Using Wordpress, you can take the edge off a 404 and make it helpful to users, and yourself, too, by emailing whenever the user clicks a link to a non-existent page. If you use this, don't forget o

You

#some variables for the script to use

#if you have some reason to change these, do.  but wordpress can handle it

$adminemail = get_bloginfo('admin_email'); #the administrator email address, according to wordpress

$website = get_bloginfo('url'); #gets your blog's url from wordpress

$websitename = get_bloginfo('name'); #sets the blog's name, according to wordpress



 if (!isset($_SERVER['HTTP_REFERER'])) {

   #politely blames the user for all the problems they caused

       echo "tried going to "; #starts assembling an output paragraph

	$casemessage = "All is not lost!";

 } elseif (isset($_SERVER['HTTP_REFERER'])) {

   #this will help the user find what they want, and email me of a bad link

	echo "clicked a link to"; #now the message says You clicked a link to...

       #setup a message to be sent to me

	$failuremess = "A user tried to go to $website"

       .$_SERVER['REQUEST_URI']." and received a 404 (page not found) error. ";

	$failuremess .= "It wasn't their fault, so try fixing it. 

       They came from ".$_SERVER['HTTP_REFERER'];

	mail($adminemail, "Bad Link To ".$_SERVER['REQUEST_URI'],

       $failuremess, "From: $websitename "); #email you about problem

	$casemessage = "An administrator has been emailed

       about this problem, too.";#set a friendly message

 }

 echo " ".$website.$_SERVER['REQUEST_URI']; ?>

and it doesn't exist.   You can click back

and try again or search for what you're looking for:

[编辑]

Add Useful Links

If you encounter a "page not found" situation on the WordPress site, it is filled with helpful links to direct you to the various categories and areas of information within the WordPress site. Check it out at http://wordpress.org/brokenlink.php.

To add similar useful links to your 404 page, create a list, or a paragraph, so the visitor can easily determine which section might be useful to visit. Information of that nature is much better than having the user just reach a dead-end. To help you understand how to link to documents within your site, especially to Pages and Categories, see Linking_Posts_Pages_and_Categories.

[编辑]

Testing 404 Error Messages

To test your custom 404 page and message, just type an URL address into your browser for your website that doesn't exist. Make one up or use something like:

http://example.com/fred.php

This is sure to result in an error unless you actually have a php file called fred. If your error page doesn't look "right", you can go back and edit it so it works correctly and matches your Theme's look and feel.

[编辑]

Help Your Server Find the 404 Page

By default, if WordPress cannot find a particular page it will look for the 404.php web page. However, there may be cases where the web server encounters a problem before WordPress is aware of it. In that case, you can still guarantee that your web server sends the visitor to your 404.php template file by configuring your web server for custom 404 error handling.

To tell your web server to use your custom error files, you'll need to edit the .htaccess file in the main directory (where main index.php file resides) of your WordPress installation. If you don't have an .htaccess file, see Editing Rewrite Rules (.htaccess) on how to create an .htaccess file.

To ensure the server finds your 404 page, add the following line to your .htaccess file:

ErrorDocument 404 /index.php?error=404

The url /index.php is root-relative, which means that the forward slash begins with the root folder of your site. If WordPress is in a subfolder or subdirectory of your site's root folder named 'wordpress', the line you add to your .htaccess file might be:

ErrorDocument 404 /wordpress/index.php?error=404

[编辑]

Questions About Error Files

Why not just hard code the path all the way to the 404.php file?: By allowing index.php to call the error file, you ensure that the 404.php file used will change automatically as you change your theme.

What happens if I switch to a theme that does not have a 404.php file?: Visitors clicking on a broken link will just see a copy of the home page of your WordPress site (index.php), but the URL they see will be the URL of the broken link. That can confuse them, especially since there is no acknowledgement of the error. But this is still better than a getting a "NOT FOUND" message without any links or information that could help them find what they seek.

[编辑]

Other Error Numbers

Here are more standard web error numbers. You can see the headers and output at Apache Status Codes and ErrorDocuments

100 Continue
101 Switching Protocols
102 Processing
200 OK
201 Created
202 Accepted
203 Non-Authoritative Information
204 No Content
205 Reset Content
206 Partial Content
207 Multi-Status
300 Multiple Choices
301 Moved Permanently
302 Found
303 See Other
304 Not Modified
305 Use Proxy
307 Temporary Redirect
400 Bad Request
401 Authorization Required
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Time-out
409 Conflict
410 Gone
411 Length Required
412 Precondition Failed
413 Request Entity Too Large
414 Request-URI Too Large
415 Unsupported Media Type
416 Requested Range Not Satisfiable
417 Expectation Failed
422 Unprocessable Entity
423 Locked
424 Failed Dependency
425 No code
426 Upgrade Required
500 Internal Server Error
501 Method Not Implemented
502 Bad Gateway
503 Service Temporarily Unavailable
504 Gateway Time-out
505 HTTP Version Not Supported
506 Variant Also Negotiates
507 Insufficient Storage
510 Not Extended

Authorization errors are handled by the WordPress program.

tysontate.com

2008-06-27T02:43:00.000-07:00

http://tysontate.com/404/

b3ta.com

2008-06-27T02:41:00.000-07:00

this site 404 page is can change beaucse it make foe flash!

thoughtbubble.cx

2008-06-27T02:38:00.000-07:00

http://www.thoughtbubble.cx/404

Not Found 404?

2008-06-27T02:37:00.000-07:00

Not Found

The requested URL /404.html was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.8 (Unix) mod_ssl/2.2.8 OpenSSL/0.9.7a mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at www.dans-blog.com Port 80

lookitsme.co.uk

2008-06-27T02:36:00.000-07:00

http://www.lookitsme.co.uk/404_me

which is I, think there is a 404 error

2008-06-27T02:35:00.000-07:00

Heya, the web server, which is I, think there is a 404 error, which means the address you typed in your browser (look up) is not a valid page that I store.

You can email webmaster-at-findmyroof.com if you think it really should be there.

I'll see you again when you click the "Back" button of your browser, or when you click here.

what this is ?404 errors?

2008-06-27T02:34:00.001-07:00

The page cannot be displayed. Hmmm.
The page you requested is probably somewhere on this site. The guy who built it is probably playing EQ or busy bouncing proxies. Maybe he just forgot to pay his hosting bill who knows. But I'm guessing the MX record for this domain is still pointing to a valid mail server so why try spamming him.

Please try the following:

* Click the refresh.gif (82 bytes) Refresh button and if you get lucky you might see something different but the chances are you that you wont.
* Make sure you typed my damn url in right its not that hard really is it, being only 5 letters and the TLD. Perhaps maybe you just use search engines instead for going direct to sites, instead of typing in the address bar?
* To check your connection settings, phone up a friend who knows what this "internet" is from your Address Book, and then proceed to try and make him Understand what the fuck you are talking about. After harrasing this Poor Soul for ages about how stupid and confusing this internet is you decide that it must be your box of noises. With this Idea in your head you should go off and investigate this problem with maybe a screwdriver and a hammer.
* If you haven't managed to Remove any of the key networking protocols / components or something else important Microsoft Windows can begin try to guess at what exactly you have done. This may Baffle you with questions such as 00EF8Dx084 but just a simple nod and a smile will do.
If you would like to randomly type error messages into a Search Engine
click Detect Settings What does 00EF8Dx084 mean?
* Some sites require you to have an IQ of at least 28 to use. If you do not meet this minimum requirement please click the File menu and then click Close. This should determine that you at least have the sufficient IQ to follow simple instructions.
* If you are trying to reach a pr0n site, make sure your door is locked, you have plenty of bandwidth and also that you have a major credit such as Visa, MasterCard etc (American Express not accepted). Remember once you have paid for pr0n dont forget that you can right click the image and Save it your hard disk for later viewing or distribution.
* Click the Back button go back to where you come from and if you didn't come from anywhere then maybe you should have done.

Server cannot be arsed or DNS Error
Internet Explorer
12.08.30: - Moving servers so should be fun and I finally get ASP WuWu!

Game-Ports -
Thirdspace - Kosch - Lamruil - Help Kosch get a free Xbox 360

hypem.com

2008-06-27T02:31:00.000-07:00

http://hypem.com/404.htm

webhex.net

2008-06-27T02:30:00.000-07:00

http://en.webhex.net/404.html

roleplaygateway.com

2008-06-27T02:28:00.000-07:00

http://www.roleplaygateway.com/404.php

lanooz.net

2008-06-27T02:23:00.000-07:00

http://lanooz.net/404.html

edg3.co.uk

2008-06-27T02:21:00.000-07:00

http://www.edg3.co.uk/404/

slonky.com

2008-06-27T02:17:00.000-07:00

http://www.slonky.com/404.html

poemofquotes

2008-06-27T02:12:00.000-07:00

http://www.poemofquotes.com/404.html

djangobook.com

2008-06-27T02:10:00.000-07:00

http://www.djangobook.com/404/

planetgeek.org

2008-06-27T02:08:00.000-07:00

http://www.planetgeek.org/404.html

BT

2008-06-27T02:05:00.000-07:00

Windows Errors or Web Server Errors?

2008-06-27T02:00:00.000-07:00

http://zonaphotoshop.com/404

The server could not locate the document you requested.

2008-06-27T01:55:00.000-07:00

The server could not locate the document you requested.

culture.gouv.fr

2008-06-27T01:53:00.000-07:00

http://www.culture.gouv.fr/index-erreur.html

Oops! You bwoke it.

2008-06-27T01:47:00.000-07:00

http://www.homestarrunner.com/404.htm

The cleanest, most concise 404 pages

2008-06-27T01:44:00.000-07:00

bmindful

2008-06-27T01:43:00.000-07:00

My God ! this site 404 page is ....

2008-06-27T01:38:00.000-07:00

My God ! this site 404 page is ....

最常见的估计就是以下的404 errors 页面了！

2008-06-27T01:36:00.000-07:00

最常见的估计就是以下的404 errors 页面了！

The page cannot be found
The page you are looking for might have been removed, had its name changed, or is temporarily unavailable.

Please try the following:

* Make sure that the Web site address displayed in the address bar of your browser is spelled and formatted correctly.
* If you reached this page by clicking a link, contact the Web site administrator to alert them that the link is incorrectly formatted.
* Click the Back button to try another link.

HTTP Error 404 - File or directory not found.
Internet Information Services (IIS)

Technical Information (for support personnel)

* Go to Microsoft Product Support Services and perform a title search for the words HTTP and 404.
* Open IIS Help, which is accessible in IIS Manager (inetmgr), and search for topics titled Web Site Setup, Common Administrative Tasks, and About Custom Error Messages.

der-vigilant

2008-06-27T01:33:00.000-07:00

this site 404pags is very cool!

ibiblio

2008-06-27T01:30:00.000-07:00

this site is http://www.ibiblio.org

404 Error Pages: Reloaded

2008-06-27T01:22:00.001-07:00

404 Error Pages: Reloaded

2008-06-27T01:08:00.000-07:00

404 Error Pages: Reloaded August 17th, 2007 in Design Showcase | 314 Comments

Three weeks ago we’ve showcased some of the most beautiful, creative and user-friendly 404 Error Pages; we’ve collected some interesting ideas one can use to help out the visitors once they got lost ony your page. We’ve also asked our readers to design their own 404 pages and promised to present the best solutions afterwards.

We’ve received over 100 entries. The choice wasn’t easy, so evaluating the quality of the entries we’ve considered - among other things - the communication with visitors, precise and clear navigation, the use of graphics, creative ideas and some outstanding solutions. Some of the solutions presented below might not be as helpful as they could or should be, however they include some creative approaches you should be aware of designing your 404 error pages.

We’d like to thank to everyone who participated, your input means a lot for us and for web-designers worldwide. You help to improve the quality of the Web. Don’t underestimate it.

So here is what you’ve come out with: over 40 working examples of user-friendly, creative and outstanding 404 error pages - in a brief overview.

此帖子创建于，至今有314个回复，足见404页面的创造力有多强！

在此贴10种类型的图上来给大家再看看：10张图？我的天！先5张吧！

Google网站管理员支持中心对于404页面的解答！

2008-06-27T01:06:00.000-07:00

Google网站管理员支持中心对于404页面的解答！
404（未找到）

服务器找不到请求的网页。例如，对于服务器上不存在的网页经常会返回此代码。

如果您的网站上没有 robots.txt 文件，而您在 Google 网站管理员工具"诊断"标签的 robots.txt 页上看到此状态，则这是正确的状态。但是，如果您有 robots.txt 文件而又看到此状态，则说明您的 robots.txt 文件可能命名错误或位于错误的位置（该文件应当位于顶级域，名为 robots.txt）。

如果对于 Googlebot 尝试抓取的网址看到此状态（在"诊断"标签的 HTTP 错误页面上），则表示 Googlebot 跟随的可能是另一个页面的无效链接（是旧链接或输入有误的链接）。

Microsoft.com下404页面，以Live Search页面取代！

2008-06-27T01:04:00.000-07:00

对于Microsoft.com域名下404错误页面，微软计划全部以Live Search页面所取代。微软表示，此举可以让用户通过搜索寻找正确的网页，而不是被滞留在404错误页面。

微软除了要改造自己的网站，还发布了一个网站管理员工具包，通过该工具包网站管理员可以修改404错误页面，让其变成一个拥有搜索引擎的页面，当然，搜索引擎可以不限于Live Search，管理员可以自由选择自己喜欢的搜索引擎。

该工具包大小1.13MB，可用于asp.net环境，任何使用IIS服务的管理员均可使用此工具进行修改。

实际上这个想法是相当不错的，微软并没有强制要求把404页面转换到自己的搜索引擎。用户可能因为自己的拼写错误或页面错误而滞留在404页面，此工具可以通过用引导的方式把用户引导到搜索结果页，从而给网站及用户创造了方便。

Strong 404!

2008-06-27T00:57:00.000-07:00

when u open http://404.jodi.org/

when u click number of first four u can look ?

when u click number of zero u can look ?

when u click number of lost four u can look ?

spore.com

2008-06-27T00:44:00.000-07:00

http://www.spore.com/fans.php or other 404 errors pages will be find!

this anthoer 404 of plinko.net

2008-06-27T00:38:00.000-07:00

this anthoer 404 of http://www.plinko.net/404/rndindex.asp

plinko

2008-06-27T00:34:00.000-07:00

http://www.plinko.net/404/rndindex.asp

The Perfect 404

2008-06-27T00:32:00.001-07:00

The Perfect 404

by Ian Lloyd

Published in: Scripting, Server Side, Usability |
Discuss this article »

Oops. Something went wrong. You’re not sure what — was it you? Was it the website? What do you do now?

Welcome to the world of the Error 404 page. You’ve requested a page — either by typing a URL directly into the address bar or clicking on an out-of-date link and you’ve found yourself in the middle of cyberspace nowhere. A user-friendly website will give you a helping hand while many others will simply do nothing, relying on the browser’s built-in ability to explain what the problem is. We can do better than that, can’t we?

I won’t go into details about how you set your server up to deliver a custom 404 page — instead, I’ll refer you to these articles:

Creating a Custom 404 Error Page (4 Guys From Rolla)
Creating Custom Error Messages in Apache (4WebHelp)

I will, however, suggest strategies for building a custom 404 page that makes the most of an otherwise lost cause.

To get started, we need to examine the most common reasons that people find themselves on a 404 page:

a mis-typed URL (or an out-of-date bookmark/favourite)
a search-engine link that is out-of-date
an internal broken link that the webmaster hasn’t noticed

They all amount to the same thing, but they need to be handled slightly differently — the 404 message needs to be customized for each eventuality. There are some tricks that you can employ that apply to all scenarios, but my first suggestion is simple...

Don’t point the finger

Tell them what went wrong, by all means, but don’t admonish the user, even if you know it’s their fault! The phrases, “might have” and “possibly” are good ones to use here. Don’t get off on the wrong foot with this visitor to your site — you might yet turn this problem around.

404 Must-haves

As well as the “something went wrong” text, you should ensure that your error page has the following:

A link to the site map (if you have one) and the home page. This is the easiest way for users to bail out. This no-brainer requires no clever scripting.
A search box. If you have a site search, add it to your 404 page. If you don’t have a site search and are in the habit of generating 404 errors, perhaps you should get one.
A distinctly minimalist look. Avoid putting all your standard site navigation on this page. You should aim to remove distractions. Besides, insisting on including a complete site navigation strip may present a maintentance overhead (your 404 page can easily lag behind the rest of the site if it is not dynamically updated with the rest of your site and the last thing you want is to have navigation on the 404 that is no longer relevant/working. Oh the irony!)

Also be sure to cut the jargon. I mean, we can talk about 404s here, right? We’re in good company. But 60-year-old Doris who got a broken link while browsing a knitting site won’t have a clue what a 404 error is. If you want to use the phrase “Error 404,” do it subtly — do it as a footnote, a nod to those who understand your freaky-deaky web speak.

Now, let’s look at how you can make the 404 work for you, instead of against you.

Let’s be intelligent about this

At this point, I should point out that this may require a certain amount of JavaScript (you may not be able to use server-side scripting to do this work, depending on your server set-up). So be sure to use the

List of HTTP status codes

2008-06-27T00:31:00.001-07:00

List of HTTP status codes · Internet

From Wikipedia, the free encyclopedia

Jump to: navigation, search

HTTP
Persistence · Compression · SSL
Headers
ETag · Cookie · Referer
Status codes
200 OK
301 Moved permanently
302 Found
403 Forbidden
404 Not Found

The following is a list of HTTP response status codes and standard associated phrases, intended to give a short textual description of the status. These status codes are specified by RFC 2616, along with additional codes (RFC 2518, RFC 2817, RFC 2295, RFC 2774, RFC 4918), some from the Distributed Authoring (WebDAV) extension. Others are unstandardised but commonly used.

The first digit of the status code specifies one of five classes of response.

[hide]

[edit] 1xx Informational

Request received, continuing process.

This class of status code indicates a provisional response, consisting only of the Status-Line and optional headers, and is terminated by an empty line. Since HTTP/1.0 did not define any 1xx status codes, servers must not send a 1xx response to an HTTP/1.0 client except under experimental conditions.

100 Continue: This means that the server has received the request headers, and that the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). If the request body is large, sending it to a server when a request has already been rejected based upon inappropriate headers is inefficient. To have a server check if the request could be accepted based on the request's headers alone, a client must send Expect: 100-continue as a header in its initial request (see RFC 2616 §14.20: Expect header) and check if a 100 Continue status code is received in response before continuing (or receive 417 Expectation Failed and not continue).^[1]
101 Switching Protocols
102 Processing (WebDAV) (RFC 2518)

[edit] 2xx Success

The action was successfully received, understood, and accepted.

This class of status code indicates that the client's request was successfully received, understood, and accepted.

200 OK: Standard response for successful HTTP requests.
201 Created: The request has been fulfilled and resulted in a new resource being created.
202 Accepted: The request has been accepted for processing, but the processing has not been completed. The request might or might not eventually be acted upon, as it might be disallowed when processing actually takes place.
203 Non-Authoritative Information (since HTTP/1.1)
204 No Content
205 Reset Content
206 Partial Content: Notice that a file has been partially downloaded. This is used by tools like wget to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.
207 Multi-Status (WebDAV): The message body that follows is an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.

[edit] 3xx Redirection

The client must take additional action to complete the request...

This class of status code indicates that further action needs to be taken by the user agent in order to fulfill the request. The action required may be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD. A user agent should not automatically redirect a request more than 5 times, since such redirections usually indicate an infinite loop.

300 Multiple Choices: Indicates multiple options for the resource that the client may follow. It, for instance, could be used to present different format options for video, list files with different extensions, or word sense disambiguation.
301 Moved Permanently: This and all future requests should be directed to the given URI.
302 Found: This is the most popular redirect code, but also an example of industrial practice contradicting the standard. HTTP/1.0 specification (RFC 1945) required the client to perform a temporary redirect (the original describing phrase was "Moved Temporarily"), but popular browsers implemented it as a 303 See Other. Therefore, HTTP/1.1 added status codes 303 and 307 to disambiguate between the two behaviours. However, the majority of Web applications and frameworks still use the 302 status code as if it were the 303.
303 See Other (since HTTP/1.1): The response to the request can be found under another URI using a GET method.
304 Not Modified: Indicates the resource has not been modified since last requested. Typically, the HTTP client provides a header like the If-Modified-Since header to provide a time against which to compare. Utilizing this saves bandwidth and reprocessing on both the server and client.
305 Use Proxy (since HTTP/1.1): Many HTTP clients (such as Mozilla ^[2] and Internet Explorer) don't correctly handle responses with this status code, primarily for security reasons.
306 Switch Proxy: No longer used.
307 Temporary Redirect (since HTTP/1.1): In this occasion, the request should be repeated with another URI, but future requests can still use the original URI. In contrast to 303, the request method should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request.

[edit] 4xx Client Error

The request contains bad syntax or cannot be fulfilled.

The 4xx class of status code is intended for cases in which the client seems to have erred. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. These status codes are applicable to any request method. User agents should display any included entity to the user. These are typically the most common codes encountered while online.

400 Bad Request: The request contains bad syntax or cannot be fulfilled.
401 Unauthorized: Similar to 403 Forbidden, but specifically for use when authentication is possible but has failed or not yet been provided. See Basic access authentication and Digest access authentication.
402 Payment Required: The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, but that has not happened, and this code has never been used.
403 Forbidden: The request was a legal request, but the server is refusing to respond to it. Unlike a 401 Unauthorized response, authenticating will make no difference.
404 Not Found: The requested resource could not be found.
405 Method Not Allowed: A request was made of a resource using a request method not supported by that resource; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource.
406 Not Acceptable
407 Proxy Authentication Required
408 Request Timeout: Client failed to continue the request
409 Conflict
410 Gone: Indicates that the resource requested is no longer available and will not be available again. This should be used when a resource has been intentionally removed; however, in practice, a 404 Not Found is often issued instead.
411 Length Required
412 Precondition Failed
413 Request Entity Too Large
414 Request-URI Too Long
415 Unsupported Media Type
416 Requested Range Not Satisfiable: The client has asked for a portion of the file, but the server cannot supply that portion (for example, if the client asked for a part of the file that lies beyond the end of the file).
417 Expectation Failed
421 There are too many connections from your internet address^{[citation needed]}
422 Unprocessable Entity (WebDAV) (RFC 4918): The request was well-formed but was unable to be followed due to semantic errors.
423 Locked (WebDAV) (RFC 4918): The resource that is being accessed is locked
424 Failed Dependency (WebDAV) (RFC 4918): The request failed due to failure of a previous request (e.g. a PROPPATCH).
425 Unordered Collection: Defined in drafts of WebDav Advanced Collections, but not present in "Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol" (RFC 3648).
426 Upgrade Required (RFC 2817): The client should switch to TLS/1.0.
449 Retry With: A Microsoft extension: The request should be retried after doing the appropriate action.

[edit] 5xx Server Error

The server failed to fulfill an apparently valid request.

Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has erred or is incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. User agents should display any included entity to the user. These response codes are applicable to any request method.

500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported
506 Variant Also Negotiates (RFC 2295)
507 Insufficient Storage (WebDAV) (RFC 4918)
509 Bandwidth Limit Exceeded: This status code, while used by many servers, is not an official HTTP status code.
510 Not Extended (RFC 2774)

[edit] See also

[edit] References

^ RFC 2616, section 8.2.3 — Use of the 100 (Continue) Status
^ Bugzilla

[edit] External links

Retrieved from "http://en.wikipedia.org/wiki/List_of_HTTP_status_codes"

Categories: HTTP | HTTP status codes | Internet-related lists

Rewrite engine

2008-06-27T00:30:00.001-07:00

Rewrite engine

From Wikipedia, the free encyclopedia

Jump to: navigation, search

In Wikipedia and other MediaWiki sites, see MediaWiki Manual:Short URL.

Please help improve this section by expanding it.
Further information might be found on the talk page or at requests for expansion.

A rewrite engine also known as URL rewriting, is software which modifies the URLs appearance, for example:

http://example.com/wiki/index.php?title=Page_title

is changed to:

http://example.com/Page_title

The benefits of a rewrite engine are^[1]:

Making website URLs more user and search engine friendly
Preventing undesired "inline linking"
Not exposing the inner workings of a web site's address to visitors

[hide]

[edit] Java and Ruby on Rails

In Java, the term "URL rewriting" sometimes describes a Web Application Server adding a session id to a URL when cookies are not supported (e.g. "index.jsp" is rewritten to "index.jsp;jsessionid=xyc" when the links are drawn in an HTML page).

Ruby on Rails has built-in URL rewriting via Routes.^[2]

[edit] See also

[edit] Notes

^ Many of these only apply to HTTP servers whose default behavior is to map URLs to filesystem entities (i.e. files and directories); certain environments, such as many HTTP application server platforms, make this irrelevant.
^ Routes.

[edit] External links

[edit] Apache

Apache's mod_rewrite: a detailed discussion of mod_rewrite's many features.
Additional Apache URL rewriting guide: more detailed discussion of mod_rewrite
Using mod_rewrite in a holistic way
mod_rewrite, a beginner's guide (with examples): a guide to get you started using mod_rewrite.
Apache mod rewrite tutorials and regular expression lessons: Mod rewrite instruction with Regular Expression syntax lessons, a how to tutorial from beginner to advanced
Rewrite URLs with mod_rewrite: a tutorial for redirecting URLs.
The Indie Publisher's mod_rewrite Recipe Book: a collection of mod_rewrite recipes especially for independent publishers.
URL Rewriting Tool
Quick introduction to mod_rewrite and when it is useful.
Useful url rewriting examples 5 common and useful url rewriting examples..

[edit] IIS

Bill Staples of Microsoft announces a new URL Rewrite Module for IIS7 which includes the ability to import Apache mod_rewrite rules
How to redirect URLs to different Web sites Microsoft Knowledgebase article on built-in URL rewriting
Scott Guthrie of Microsoft describes various techniques for URL rewriting in .NET

[edit] Rewrite engines

Apache Software Foundation's Apache HTTP server

mod_rewrite Apache module described as "the Swiss Army knife of URL manipulation".^{[citation needed]}
mod_alias Simpler Apache module allow for manipulation and control of URLs as requests arrive at the server..

Microsoft's Internet Information Server (IIS)

URL Rewrite Module for IIS 7.0 from Microsoft
IIS Mod-Rewrite from Micronovae
IISRewrite from Qwerksoft
ISAPI_Rewrite from Helicon Tech
URL Replacer from Motobit
Ionic's ISAPI Rewrite Filter (IIRF) free and open source, written in C, requires no .NET, works with ASP.NET PHP Ruby JSP CFML etc; IIS5/6/7.
.NET URL Rewriter and Reverse Proxy Free professional URL rewriting and reverse proxy package. Supports .NET 2.0, 3.5, IIS 6, IIS 7.
VirtualUrl.NET Professional URL rewriting package.
UrlRewriter.NET Free, open-source package. Supports .NET 1.1 and 2.0.
URLRewriting.NET, free and open source supports, ASP.NET 2.0
VirtualUrl.NET for ASP.NET 2 Professional URL rewriting package.

Java 2 Platform, Enterprise Edition (J2EE) Servlet container servers (such as Apache Tomcat, Resin, Orion etc):

HttpRedirectFilter (open source)
UrlRewriteFilter (open source - BSD) - allows you to rewrite URLs before they get to your Sea

Retrieved from "http://en.wikipedia.org/wiki/Rewrite_engine"

Categories: URI scheme

Link rot

2008-06-27T00:29:00.002-07:00

Link rot

From Wikipedia, the free encyclopedia

Jump to: navigation, search

Link rot (or linkrot) is the process by which links on a website gradually become irrelevant or broken as time goes on, because websites that they link to disappear, change their content or redirect to new locations.

The phrase also describes the effects of failing to update web pages so that they become out-of-date, containing information that is old and useless, and that clutters up search engine results.

[hide]

[edit] Prevalence

The 404 "not found" response is familiar to even the occasional Web user. A number of studies have examined the prevalence of link rot on the Web, in academic literature, and in digital libraries. In a 2003 experiment, Fetterly et al. (2003) discovered that about one link out of every 200 disappeared each week from the internet. McCown et al. (2005) discovered that half of the URLs cited in D-Lib Magazine articles were no longer accessible 10 years after publication, and other studies have shown link rot in academic literature to be even worse (Spinellis, 2003, Lawrence et al., 2001). Nelson and Allen (2002) examined link rot in digital libraries found that about 3% of the objects were no longer accessible after one year.

Some news sites contribute to the link rot problem by keeping only recent news articles online where they are freely accessible at their original URLs, then removing them or moving them to a paid subscription area. This causes a heavy loss of supporting links in sites discussing newsworthy events and using news sites as references.

[edit] Discovering

Detecting link rot for a given URL is difficult using automated methods. If a URL is accessed and returns back an HTTP 200 (OK) response, it may be considered accessible, but the contents of the page may have changed and may no longer be relevant. Some web servers also return a soft 404, a page returned with a 200 (OK) response (instead of a 404) that indicates the URL is no longer accessible. Bar-Yossef et al. (2004) developed a heuristic for automatically discovering soft 404s.

[edit] Combating

The WordPress blog publishing systems implements a guard against link rot. If an author renames a link, the old link automatically redirects to the new location.^[1]

[edit] Web archiving

To combat link rot, web archivists are actively engaged in collecting the Web or particular portions of the Web and ensuring the collection is preserved in an archive, such as an archive site, for future researchers, historians, and the public. The largest web archiving organization is the Internet Archive Wayback Machine, which strives to maintain an archive of the entire Web, taking periodic snapshots of pages that can then be accessed for free and without registration many years later simply by typing in the URL. National libraries, national archives and various consortia of organizations are also involved in archiving culturally important Web content.

Individuals may also use a number of tools that allow them to archive web resources that may go missing in the future:

WebCite, a tool specifically for scholarly authors, journal editors and publishers to permanently archive "on-demand" and retrieve cited Internet references (Eysenbach and Trudel, 2005).
Archive-It, a subscription service that allows institutions to build, manage and search their own web archive
hanzo:web is a personal web archiving service created by Hanzo Archives that can archive a single web resource, a cluster of web resources, or an entire website, as a one-off collection, scheduled/repeated collection, an RSS/Atom feed collection or collect on-demand via Hanzo's open API.

[edit] Webmasters

Webmasters have developed a number of best practices for combating link rot:

Avoiding unmanaged hyperlink collections
Avoiding links to pages deep in a website ("deep linking")
Using hyperlink checking software or a Content Management System (CMS) that automatically checks links
Using permalinks
Using redirection mechanisms (e.g. "301: Moved Permanently") to automatically refer browsers and crawlers to the new location of a URL

[edit] Authors citing URLs

A number of studies have shown how wide-spread link rot is in academic literature (see below). Authors of scholarly publications have also developed best-practices for combating link rot in their work:

Avoiding URL citations that point to resources on a researcher's personal home page (McCown et al., 2005)
Using Persistent Uniform Resource Locators (PURLs) and digital object identifiers (DOIs) whenever possible
Using web archiving services (e.g. WebCite) to permanently archive and retrieve cited Internet references (Eysenbach and Trudel, 2005).

[edit] See also

[edit] References

^ Rønn-Jensen, Jesper (2007-10-05). Software Eliminates User Errors And Linkrot. Justaddwater.dk. Retrieved on 2007-10-05.

[edit] Further reading

[edit] Link rot on the Web

Ziv Bar-Yossef, Andrei Z. Broder, Ravi Kumar, and Andrew Tomkins (2004). "Sic transit gloria telae: towards an understanding of the Web’s decay". Proceedings of the 13th international conference on World Wide Web: 328–337.

Tim Berners-Lee (1998). "Cool URIs Don’t Change".

Gunther Eysenbach and Mathieu Trudel (2005). "Going, going, still there: using the WebCite service to permanently archive cited web pages". Journal of Medical Internet Research 7 (5). doi:10.2196/jmir.7.5.e60.

Dennis Fetterly, Mark Manasse, Marc Najork, and Janet Wiener (2003). "A large-scale study of the evolution of web pages". Proceedings of the 12th international conference on World Wide Web.

Wallace Koehler (2004). "A longitudinal study of web pages continued: A consideration of document persistence". Information Research 9 (2).

John Markwell and David W. Brooks (2002). "Broken Links: The Ephemeral Nature of Educational WWW Hyperlinks". Journal of Science Education and Technology 11 (2): 105–108. doi:10.1023/A:1014627511641.

[edit] In academic literature

Robert P. Dellavalle, Eric J. Hester, Lauren F. Heilig, Amanda L. Drake, Jeff W. Kuntzman, Marla Graber, Lisa M. Schilling (2003). "Going, Going, Gone: Lost Internet References". Science 302 (5646): 787–788. doi:10.1126/science.1088234. PMID 14593153.

Steve Lawrence, David M. Pennock, Gary William Flake, Robert Krovetz, Frans M. Coetzee, Eric Glover, Finn Arup Nielsen, Andries Kruger, C. Lee Giles (2001). "Persistence of Web References in Scientific Research". Computer 34 (2): 26–31. doi:10.1109/2.901164.

Wallace Koehler (1999). "An Analysis of Web Page and Web Site Constancy and Permanence". Journal of the American Society for Information Science 50 (2): 162–180. doi:10.1002/(SICI)1097-4571(1999)50:2<162::aid-asi7>3.0.CO;2-B.

Frank McCown, Sheffan Chan, Michael L. Nelson, and Johan Bollen (2005). "The Availability and Persistence of Web References in D-Lib Magazine". Proceedings of the 5th International Web Archiving Workshop and Digital Preservation (IWAW'05).

Carmine Sellitto (2005). "The impact of impermanent Web-located citations: A study of 123 scholarly conference publications". Journal of the American Society for Information Science and Technology 56 (7): 695–703. doi:10.1002/asi.20159.

Diomidis Spinellis (2003). "The Decay and Failures of Web References". Communications of the ACM 46 (1): 71–77. doi:10.1145/602421.602422.

[edit] In digital libraries

Michael L. Nelson and B. Danette Allen (2002). "Object Persistence and Availability in Digital Libraries". D-Lib Magazine 8 (1). doi:10.1045/january2002-nelson.

[edit] External links

Future-Proofing Your URIs
Jakob Nielsen, "Fighting Linkrot", Jakob Nielsen's Alertbox, June 14, 1998.
Warrick - a tool for recovering lost websites from the Internet Archive and search engine caches
Pagefactor - user-contributed database of moved URLs

Retrieved from "http://en.wikipedia.org/wiki/Link_rot"

Categories: World Wide Web

.htaccess

2008-06-27T00:29:00.001-07:00

.htaccess · Internet

From Wikipedia, the free encyclopedia

Jump to: navigation, search

In the Apache web server, .htaccess (hypertext access) is the default name of directory-level configuration files. A .htaccess file is placed in a particular directory, and the directives in the .htaccess file apply to that directory, and all subdirectories thereof. It provides the ability to customize configuration for requests to the particular directory. The file name starts with a dot because dot-files are by convention hidden files on Unix-like operating systems.

[hide]

[edit] Common usage

Authorization, authentication: .htaccess files are often used to specify the security restrictions for the particular directory, hence the filename "access". The .htaccess file is often accompanied by an .htpasswd file which stores valid usernames and their passwords.
Customized error responses: Changing the page that is shown when a server-side error occurs, for example HTTP 404 Not Found.
Rewriting URLs: Servers often use .htaccess to rewrite "ugly" URLs to shorter and prettier ones.
Cache Control: .htaccess files allow a server to control User agent caching used by web browsers to reduce bandwidth usage, server load, and perceived lag.

[edit] When .htaccess files should be used

For servers with multiple users, as is common in shared web hosting plans, it is often desirable to allow individual users the ability to alter their site configuration. In general, .htaccess files should be used by users who do not have access to the main server configuration files. ^[1]

[edit] When .htaccess files should not be used

To control Apache, using the main server configuration file httpd.conf^[2] is preferred for security and performance reasons.^[3]

Performance loss - for each HTTP request there are additional file-system accesses for every parent directory when using .htaccess
Security - allowing individual users to modify the configuration of a server can cause security concerns if not set up properly.

[edit] See also

[edit] External links

[edit] References

^ Apache Tutorial: When (not) to use .htaccess files. Retrieved on 2008-01-12.
^ Configuration Files - Apache HTTP Server. Retrieved on 2008-01-12.
^ When Not to use .htaccess files

This World Wide Web-related article is a stub. You can help by expanding it.

Retrieved from "http://en.wikipedia.org/wiki/.htaccess"

Categories: World Wide Web stubs | Configuration files | Web technology

Dead link

2008-06-27T00:28:00.000-07:00

Dead link

From Wikipedia, the free encyclopedia

Jump to: navigation, search

This page refers to pages on the world wide web. For broken links in Wikipedia, see Wikipedia:Using the Wayback Machine, Wikipedia:Dead external links and Special:BrokenRedirects.

A dead link or broken link is a link on the world wide web that points to a web page or server that is permanently unavailable. The most common result of a dead link is a 404 error, which indicates that the web server responded, but the specific page could not be found. The browser may also return a DNS error indicating that a web server could not be found at that domain name. A link might also be dead because of some form of blocking such as content filters or firewalls.

Another type of dead link is a URL that points to a site unrelated to the content sought. This can sometimes occur when a domain name is allowed to lapse, and is subsequently reregistered by another party. Domain names acquired in this manner are attractive to those who wish to take advantage of the stream of unsuspecting surfers that will inflate hit counters and PageRanking.

Link rot is the process by which links on a website gradually become irrelevant or broken over time as sites they link to disappear, change content, or redirect to new locations.

Links specially crafted to not resolve, as a type of meme, are known as Zangelding, which roughly translated from Dutch means tangle thing. A zangelding is basically a list of self referencing broken links.

Dead links commonplace on the Internet can also occur on the authoring side, when website content is assembled, copied, or deployed without properly verifying the targets, or simply not kept up to date. Because broken links are to some very annoying, generally disruptive to the user experience, and can live on for many years, sites containing them are regarded as unprofessional.

[edit] See also

[edit] External links

‹The stub template below is included via a redirect that has been proposed for deletion. See stub types for deletion to help reach a consensus on what to do.›

This article related to telecommunication is a stub. You can help Wikipedia by expanding it.

Retrieved from "http://en.wikipedia.org/wiki/Dead_link"

Categories: Network addressing | Telecommunications stubs

From Wikipedia, the free encyclopedia

2008-06-27T00:27:00.000-07:00

Jump to: navigation, search

HTTP
Persistence · Compression · SSL
Headers
ETag · Cookie · Referer
Status codes
200 OK
301 Moved permanently
302 Found
403 Forbidden
404 Not Found

The 404 or Not Found error message is an HTTP standard response code indicating that the client was able to communicate with the server but either the server could not find what was requested, or it was configured not to fulfill the request and did not reveal the reason why. 404 errors should not be confused with "server not found" or similar errors, in which a connection to the destination server could not be made at all.

[hide]

[edit] Overview

A screenshot of a 404 error in Wikipedia with Camino.

When communicating via HTTP, a server is required to respond to a request, such as a web browser's request for an HTML document (web page), with a numeric response code and an email-like MIME message. In the code 404, the first "4" indicates a client error, such as a mistyped URL. The following two digits indicate the specific error encountered. HTTP's use of three-digit codes is similar to the use of such codes in earlier protocols such as FTP and NNTP.

At the HTTP level, a 404 response code is followed by a human-readable "reason phrase". The HTTP specification suggests the phrase "Not Found"^[1] and many web servers by default issue an HTML page that includes both the 404 code and the "Not Found" phrase. Webservers can typically be configured to display a more natural description, a branded page or sometimes a search form, but the protocol level phrase, which is hidden from the user, is rarely customized.

Internet Explorer (before Internet Explorer 7), however, will not display custom pages unless they are larger than 512 bytes, opting to instead display a "friendly" error page. This default behaviour can be changed under Tools | Internet Options by clicking on the Advanced tab and un-checking the "Show friendly HTTP error messages" check box.

A 404 error is often returned when pages have been moved or deleted. In the first case, a better response is to return a 301 Moved Permanently response, which can be configured in most server configuration files, or through URL rewriting; in the second case, a 410 Gone should be returned. Because these two options require special server configuration, most websites do not make use of them.

404 errors should not be confused with DNS errors, which appear when the given URL refers to a webserver which does not exist. These are not 404 errors, which are always returned by a webserver.

The term "404", incidentally, is also sometimes used as an obscure gibe, the implication being that nobody's home upstairs: "He's a 404."

[edit] False 404 errors

Some websites report a "not found" error by returning a standard web page with a "200 OK" response code; this is called a soft 404. Soft 404s are problematic for automated methods of discovering whether a link is broken.

Some proxy servers generate a 404 error when the remote host is not present, rather than returning lower level errors such as hostname lookup failing, or "connection refused". This can confuse programs that expect and act on specific responses -they can no longer easily distinguish between an absent web server and a missing web page on a web server that is present.^{[citation needed]}

In July 2004, the UK telecom provider BT Group deployed the Cleanfeed content blocking system, which returns a 404 error to any request for content identified as illegal by the Internet Watch Foundation. Governments that censor the Internet also often return a fake 404 error when a user tries to access a blocked website.^{[citation needed]}

[edit] See also

[edit] References

^ 6.1.1 Status Code and Reason Phrase. Retrieved on 22 June 2008.

[edit] External links

ErrorDocument Directive - instructions on custom error pages for the Apache 2.0 web server
The Perfect 404 - Guide to building a custom 404 page

什么是404页面？

2008-06-27T00:05:00.000-07:00

404页面就是当用户输入了错误的链接时，返回的页面。

404页面的目的是：
告诉浏览者其所请求的页面不存在或链接错误，同时引导用户使用网站其他页面而不是关闭窗口离开。

404页面该怎么做？

很多开源系统包括CMS系统、Blog系统等不提供404页面或提供的404页面并未达到SEO的要求，这让网站的权威性大打折扣。

404页面该达到怎么样的效果才符合SEO要求？

搜索引擎通过HTTP状态码来识别网页的状态。当搜索引擎获得了一个错误链接时，网站应该返回404状态码，告诉搜索引擎放弃对该链接的索引。而如果返回200或302状态码，搜索引擎就会为该链接建立索引，这导致大量不同的链接指向了相同的网页内容。

结果是，搜索引擎对该网站的信任度大幅降低。——很多网站存在这个问题：404页面返回的是200或302状态码而不是404状态码。

正确建立404页面的方法是：（仅适合Apache服务器）

* 在.htaccess 文件中加入代码： ErrorDocument 404 /Error.html
* 建立一个简单的html404页面命名 Error.html
* 把 Error.html放置在网站根目录
注意：
* 不要将404错误直接转向到网站首页，这将导致首页不被收录；
* /Error.html 前面不要带主域名，否者返回的状态码是302或200状态码。

404pages Blog!

404!

Today found this page!

Creating an Error 404 Page In WordPress Blog

Creating an Error 404 Page

From WordPress Chinese

目录

An Ounce of Prevention

Understanding Web Error Handling

Editing an Error 404 Page

Error 404 - Not Found

Creating an Error 404 Page

Advanced 404.php Example

$AA_REASON_PHRASE

Tips for Error Pages

Sending Proper Headers

Writing Friendly Messages

Add Useful Links

Testing 404 Error Messages

Help Your Server Find the 404 Page

Questions About Error Files

Other Error Numbers

tysontate.com

b3ta.com

thoughtbubble.cx

Not Found 404?

lookitsme.co.uk

which is I, think there is a 404 error

what this is ?404 errors?

hypem.com

webhex.net

roleplaygateway.com

lanooz.net

edg3.co.uk

slonky.com

poemofquotes

djangobook.com

planetgeek.org

BT

Windows Errors or Web Server Errors?

The server could not locate the document you requested.

culture.gouv.fr

Oops! You bwoke it.

The cleanest, most concise 404 pages

bmindful

My God ! this site 404 page is ....

最常见的估计就是以下的404 errors 页面了！

der-vigilant

ibiblio

404 Error Pages: Reloaded

404 Error Pages: Reloaded

Google网站管理员支持中心对于404页面的解答！

Microsoft.com下404页面，以Live Search页面取代！

Strong 404!

spore.com

this anthoer 404 of plinko.net

plinko

The Perfect 404

The Perfect 404

by Ian Lloyd

Don’t point the finger

404 Must-haves

Let’s be intelligent about this

List of HTTP status codes

List of HTTP status codes · Internet

From Wikipedia, the free encyclopedia

Contents

[edit] 1xx Informational

[edit] 2xx Success

[edit] 3xx Redirection

[edit] 4xx Client Error

[edit] 5xx Server Error

[edit] See also

[edit] References

[edit] External links

Rewrite engine

Rewrite engine

From Wikipedia, the free encyclopedia

Contents

[edit] Java and Ruby on Rails