function addEvent( obj, type, fn ) {
  if ( obj.attachEvent ) {
    obj['e'+type+fn] = fn;
    obj[type+fn] = function(){obj['e'+type+fn]( window.event );}
    obj.attachEvent( 'on'+type, obj[type+fn] );
  } else
    obj.addEventListener( type, fn, false );
}

function doPopups() {
   if (!document.getElementsByTagName) return false;
   var links = document.getElementsByTagName("a");
   for (var i=0; i < links.length; i++) {
     if (links[i].className.match("popup_page")) {
       links[i].onclick = function() {
         window.open(this.href, "", "top=40,left=40,width=790,height=530,scrollbars=yes");
         return false;
       }
     }
   }
 }

addEvent(window, "load", doPopups);