var AdUnitObj = Class.create();
AdUnitObj.prototype = {
  initialize: function(id, readXMLAsStringFlag, collapsable, targetParam, randomKey) {
    this.id = id;
    this.readXMLAsString = readXMLAsStringFlag;
    this.collapsable = collapsable;
    this.targetParam = targetParam;
    this.randomKey = randomKey;
  },
  // register ajax callback function with prototype
  notify: function(responseEle, callbackParam) {
    if (responseEle.childNodes[0].nodeValue == 'refresh') {
      var src = _getAdUrl(this.targetParam, this.randomKey );
      if (this.collapsable) {
        pingAdServer( paramKey, this.id, content);
      } else {
        $(this.id).src = src;
      }
    }
  },

  toggleLoad: function(onLoading) {
  }
}