function centerWindow(url,title,width,height){
	x=(screen.width-width)/2;	
	y=(screen.height-height)/2;	
	win=window.open(url,'','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,width='+width+',height='+width+',top='+y+',left='+x);
	win.focus();
}