Apache is an open-source HTTP server, and is used to serve your site. Apache handlers tell the server how to deal with web files that need to be processed on the server. For example, Apache is set up to process files with .pl extensions using Perl. However, if for some reason you also wanted to process files with .script extension using Perl, then you would have to set up a custom Apache handler for your site.
Note: People often get confused as to the difference between Mime types and Apache handlers. Basically, Mime types tell your browser how to handle files, while Apache handlers tell the server how to handle files.
Warning: Check with your hosting administrator before adding an Apache handler, as they can easily alter the correct functioning of your web site.
To add an Apache handler:
Click on the Apache Handlers link in the Advanced Menu area.
Enter the file extension in the Extension(s) field. You need to add the . before the extension name.
Enter the Apache handler in the Handler field. Have a look at the list of system-wide Apache handlers to show you how to add a new one or add to a pre-existing one.
Click on the button.