function doSitePopup(url) {

	var w = 775;
	var h = 443;
	
		if (document.all) {
		   w = document.body.clientWidth;
		   h = document.body.clientHeight;
		} else if (document.layers) {
		   w = window.innerWidth;
		   h = window.innerHeight;
		}
	
	var popW = 775;
	var popH = 443;
	
	var leftPos = (w-popW)/2;
	var topPos = (h-popH)/2;
	
	window.open(url,'sitepopup','width=' + popW + ',height='+popH+',top='+topPos+',left='+leftPos);

}