You most likely have seen some kind of form on the web that asks you for all types of information. That form is written in HTML and maybe gets enhanced with JavaScript. When you click the submit button, the Back End Perl script takes all that information from the Front End and processes it. That is one major difference between JavaScript and Perl. JavaScript is not a CGI-capable language and Perl or even Java is.
Some people see that as a disadvantage.
I see it as an advantage. JavaScript may not be able to communicate with the server like a Perl script but that makes the language less complicated and easier to learn. You won't hear anyone boasting about the power of JavaScript as the universal solution to all your programming needs. It is just there to help make your web pages better. Keeping that in mind, you should now be ready to focus on just JavaScript and its Object Model.