function popup(url) {
	var x = screen.width;
	var y = screen.height;
	var width = 550;
	var height = 600;
	var top = parseInt( ( y - height ) / 2 ) ;
	var left = parseInt( ( x - width  ) / 2 ) ;
	var  props = "toolbars=no,location=no,status=no,scrollbars=yes,resizable=yes,width=" + width + ",height=" + height + ",left=" + left + ",top=" + top;
	window.open(url,'newWin',props);
}