function popup(url,imageHeight,imageWidth) {
	var myWin; 
	var y=(screen.height/2)-(imageHeight/2);
	var x=(screen.width/2)-(imageWidth/2);
	myWin = window.open(url, "","width="+imageWidth+",height="+imageHeight+",toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,top="+y+",left="+x);
	myWin.focus();
	void(0);
}