404 Error - The Page Cannot be Found
A "404 Error" happens when the web server you are on cannot find the page that you requested. This type of error is quite common and is seen all over the place.
404 Errors can be caused by many different problems, though generally they are caused by either dead links, or errors in the websites coding. Dead links often occur when a webmaster puts external links on his website, then the website he is referring to changes, moves, or no longer exists. Coding errors on the other hand can happen all over the place! Quite often webmasters neglect to check their links as they are making them, this means that there could be a spelling mistake in the URL, a missing slash or pretty much any typing error you could think of. It's good practice to check all links as you make them!
Internal links, or links to pages within the same website also get 404 errors from time to time. Unfortunately this is due to the webmasters neglect of his own website. If modifications were made to the website, he should have checked his website, or ran an automated program to check all of his links. Broken internal links look bad and unprofessional.
There are a few ways that a webmaster can mask his errors, or at least do some recovery work if an error occurs. If a webmaster changes the framework of his website he can create re-direct pages that will move the user to their the main index, or the updated version of the page that they requested. Additionally, they should be able to stop 404 Errors all together by creating an automatic forward whenever an error occurs.
A couple tricks for webmasters to help reduce the amount of 404 errors, or try to hide the errors is to modify the. htaccess file in their website directory. This file has one variable that can be set that will allow you to specify the page that you want to send the user, should a 404 occur.
Example: ErrorDocument 404 index. php
Example: ErrorDocument 404 404.php
The first example would automatically send the user back to the main index (if the main index was called index. php), and the second would send them to a customized 404.php file, which could display an error message, or send you an auto-notification of an error that happened. Keep in mind that if you use non-absolute directories that you may not feed out the correct page. For instance if the error occurs in a subdirectory on your website, and you specify index. php as your error document, there may not be an index. php in that subfolder, thus it might be a good idea to put the below example instead.
Example: ErrorDocument 404 http://www. yoursite. com/
Note: If you use Apache HTTPD you can setup the default error documents in the configuration file!