l=window.location.search
if (l.indexOf("tab")!=-1) {
	s1=l.split("&");
	flag=0;
	for (var i=0;i<s1.length;i++) {
		s2=s1[ i].split("=");
		if (s2[0].match(/^[\?]{0,1}tab$/))
			flag=s2[1];
	}
	TabbedPanels1.showPanel(Number(flag)); 
}

Put that right after the code inserted at the end of the page:

var TabbedPanels1 = new Spry.Widget.TabbedPanels("TabbedPanels1");

Where the TabbedPanels1 is the name of the panels (change this in your code to match your page's tab names)

Then to make a page load a different tab when loaded in a browser, append the URL with tab=## where the ## is from 0 to the number of tabs-1 - this is a JS array which starts with 0, so the tab=0 sets the first tab (which is the default action), while tab=3 opens the fourth tab. This tab=## can appear anywhere in the querystring URL.