Board Thread:Support Requests - Getting Technical/@comment-2255188-20130519021024/@comment-3335785-20130520063525

From what I can tell, jQuery parses the entire page looking for classes and applies the changes to every class. It uses javascript's native  where possible as seen in the documentation. If you ran that code from your console, it turns the following two lines red:
 * testing, testing
 * 1, 2, 3

isn't used in the way shown above in the documentation, I suspect it's some sort of shorthand loop syntax, athough I've never used it myself.