function centerWin(url, width, height)
{
	var centerX=(screen.width-width)/2; 
	var centerY=(screen.height-height)/2;
	newwindow = window.open(url, 'centerWin', 'top='+centerY+',screenY='+centerY+',left='+centerX+',screenX='+centerX+',width='+width+',height='+height+',toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=no');
}