Perl is a popular scripting language that is that is used to build different web-oriented apps, which includes CGI scripts. Among the features which differentiate it from various other languages is the use of modules - parts of Perl code that perform predefined jobs and they're widely accepted. In simple terms, as an alternative to generating custom program code to perform something or pasting tens and hundreds of lines of code in your script, you can "call" some module that is already available for this specific job and use only a few lines of program code. This way, your script shall be executed more rapidly since it'll be much smaller. Employing modules will, in addition make your script simpler to change considering that you'll need to go through a smaller amount of code. If you wish to use Perl on your website, you need to ensure that the needed modules are present on the server.