code: function (oTarget, sEventType, fnHandler) {
    if (oTarget.listeners && oTarget.listeners[sEventType]) {
      var listeners = oTarget.listeners[sEventType];
      for (var i = listeners.length - 1; i >= 0 && fnHandler; i--) {
        if (listeners[i] == fnHandler) {
          listeners.splice(i, 1);
        }
      }
      if ((!listeners.length || !fnHandler) && listeners["_handler"]) {
        oTarget.removeEventListener ? oTarget.removeEventListener(sEventType, listeners["_handler"], false) : oTarget.detachEvent('on' + sEventType, listeners["_handler"]);
        delete oTarget.listeners[sEventType];
      }
    }
  }
docs: /*注销事件
  @param {Object} oTarget 对象
  @param {String} sEventType 事件类型
  @param {Function} fnHandler 事件方法