The first use of the .htaccess file is custom error pages. These will allow you to have your own, personal error pages (for example when a file is not found) instead of using your host's error pages or having no page. This will make your site seem much more professional in the unlikely event of an error. It will also allow you to create scripts to notify you if there is an error (for example I use a PHP script on Free Webmaster Help to automatically e-mail me when a page is not found).
You can use custom error pages for any error as long as you know its number (like 404 for page not found) by adding the following to your .htaccess file:
ErrorDocument errornumber /file.html
For example if I had the file notfound.html in the root directory of my site and I wanted to use it for a 404 error I would use:
ErrorDocument 404 /notfound.html
If the file is not in the root directory of your site, you just need to put the path to it:
ErrorDocument 500 /errorpages/500.html
These are some of the most common errors:
401 - Authorization Required
400 - Bad request
403 - Forbidden
500 - Internal Server Error
404 - Wrong page
Then, all you need to do is to create a file to display when the error happens and upload it and the .htaccess file.
