Basic Java code

This should be really easy for anyone that knows javascript. I am using a third party hosted app called kickapps. "Each KickApps-powered page type has a different class applied to #ka_mainContainer. So to apply JS to a specific page type, all you have to do is figure out the class of the page type that you want to target, and then wrap your JS in an if-statement that makes sure that #ka_mainContainer has this class, like this:.... (see attached word doc) this should be easy. I just need someone to show me how to insert "content" I have attached more detailed info. Jon