function openChat(varUrl) {
 var winleft=(screen.width-700)/2;
 var wintop=(screen.height-450)/2;
 window.open(varUrl,'chat','toolbar=0,location=0,status=1,menubar=0,scrollbars=0,resizable=1,width=700,height=450,top='+wintop+',left='+winleft);
}