Action Script Newbie (Calling a URL)

All, sorry I know this is probably an easy one, but I am a flash newbie and trying to learn what I can. Basically, I have the code for a simple MouseEvent.CLICK.
(I watched the Lynda.com Flash videos.)
//nav buttons

var nextSection:String = "TEST1";

function onHomeClick(evt:MouseEvent):void {
nextSection ="TEST2";
trace(nextSection);
}

push_btn.addEventListener(MouseEvent.CLICK,onHomeClick);

This works fine, so I understand the concept, so how do I open a webpage to any website. Would like for it to open in a different window.

Thanks