function dss_addEvent(el,etype,fn) {
  if(el.addEventListener && (!window.opera || opera.version) &&
  (etype!='load')) {
    el.addEventListener(etype,fn,false);
  } else if(el.attachEvent) {
    el.attachEvent('on'+etype,fn);
  } else {
    if(typeof(fn) != "function") return;
    if(typeof(window.earlyNS4)=='undefined') {
      // to prevent this function from crashing Netscape versions before 4.02
      window.earlyNS4=((navigator.appName.toLowerCase()=='netscape')&&
      (parseFloat(navigator.appVersion)<4.02)&&document.layers);
    }
    if((typeof(el['on'+etype])=="function")&&!window.earlyNS4) {
      var tempFunc = el['on'+etype];
      el['on'+etype]=function(e){
        var a=tempFunc(e),b=fn(e);
        a=(typeof(a)=='undefined')?true:a;
        b=(typeof(b)=='undefined')?true:b;
        return (a&&b);
      }
    } else {
      el['on'+etype]=fn;
    }
  }
}