function gotosite(url){

   if((top.website == null) || (top.website.closed)){
      top.website = open(url,"website","width=640,height=480,toolbar,resizable,scrollbars=yes,status,titlebar,menubar,location");
   }else{
      top.website.location = url;
   }
   top.website.focus();
}

function killwindow(){

   if((top.website != null) && !(top.website.closed)){
      top.website.close();
   }
}