Parsing html data from a site which uses javascript to populate

I know we can parse remote site's html by using simple_HTML_Dom class.It is pretty easy!.

What i would like to know i开发者_开发百科s that i am looking to parse a data of remote site's html' whose get populated by some JS/jquery/AJAX.How one can get that data? What is the trick?

ThankYou in Advance!

You can write a Firefox plugin using XUL/JS and parse the populated DOM if you need to.