function popup(url)
{
 window.name='main';
 width=700;
 height=850;
 Agent= navigator.userAgent.toLowerCase();
 isOpera = (Agent.indexOf("opera") != -1);
 //Center PopUp
 centerx=(screen.width-width)/2;
 if (isOpera) centery=(screen.height-height)/4;
 else centery=(screen.height-height)/2;
 window.open(url,'popup',"toolbar=no,height="+height+",width="+width+",scrollbars=yes,resizable=yes");
 return false;
}