code: function (oTarget, sEventType, fnHandler) {
    oTarget.listeners = oTarget.listeners || {};
    var listeners = oTarget.listeners[sEventType] = oTarget.listeners[sEventType] || [];
    listeners.push(fnHandler);
    if (!listeners["_handler"]) {
      listeners["_handler"] = function (e) {
        var e = e || window.event;
        for (var i = 0, fn; fn = listeners[i++];) {
          fn.call(oTarget, e)
        }
      }
      oTarget.addEventListener ? oTarget.addEventListener(sEventType, listeners["_handler"], false) : oTarget.attachEvent('on' + sEventType, listeners["_handler"]);
    }
  }
docs: /*添加事件
  @param {Object} oTarget 对象
  @param {String} sEventType 事件类型
  @param {Function} fnHandler 事件方法