What's the role of javascript? How does it work?

Javascript is a scripting language that is used extensively on HTML webpages. It is basically a list of instructions that are intrepreted by the webbrowser and control the behaviour of elements on a webpage.

There are a lot of resources about javascript on the internet, here's one of them you maybe interested.
http://www.w3schools.com/JS/default.asp

this link will help u :)

what do you mean?
http://msconline.maconstate.edu/tutorials/
take that site i studied java script from it...
its pretty easy...
javascript is functions...