function popup_open(url, name, width, height, params)
{
	if (!name)
		name = "WIN";
	
	if (!params) {
		var left = "left="+((screen.width/2) - (width/2))+",";
		var top  = "top="+((screen.height/2) - (height/2));
		params = left + top + ",scrollbars=yes,toolbar=no,menubar=no,location=no,directories=no,status=yes";
	} else
		params = "," + params;
	
	wIM = window.open(url, name, "width="+ width +",height="+ height + "," + params);
	wIM.focus();
	
	return false;
}