Hello. Although the file you are working on is a perl file, the section of code that you have provided is javascript instead (you can see at the top that it's a script section, written in javascript). The perl part is what the server will execute to create the page, and the javascript part is sent in the content to be executed by the browser (IE, Chrome...).

So this is not the right place for this question, maybe you can try Stack Overflow instead.