You've got a couple of options:
1. You can dissect the source of the page to determine from where the javascript is getting it's data. It may lead back to a json, rest, xml, or soap URL that you can use directly.
2. Have a look at PhantomJS. It's basically a scriptable, headless Webkit based browser that will render the page as would a normal browser and allow you to script/parse the resultant data.
http://phantomjs.org/Terry