whole_func_string: function addEvent(el, type, handler) {
    var once = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;
    var capture = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : false;
  
    if (capture !== undefined && !isBoolean(capture) && supportsPassive) {
      capture = { passive: true };
    }
    if (once) {
      var oldHandler = handler;
      handler = function () {
        return function () {
          for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
            args[_key] = arguments[_key];
          }
  
          oldHandler.apply(this, args);
          removeEvent(el, type, handler, once, capture);
        };
      }();
      /* 将包装后的方法记录到缓存中 */
      addEventCache(el, type + '_once', oldHandler, handler);
    }
  
    el.addEventListener(type, handler, capture);
  }
func_code_string: function addEvent(el, type, handler) {
    var once = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;
    var capture = arguments.length > 4 && arguments[4] !== undefined ? arguments[4] : false;
  
    if (capture !== undefined && !isBoolean(capture) && supportsPassive) {
      capture = { passive: true };
    }
    if (once) {
      var oldHandler = handler;
      handler = function () {
        return function () {
          for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
            args[_key] = arguments[_key];
          }
  
          oldHandler.apply(this, args);
          removeEvent(el, type, handler, once, capture);
        };
      }();
      /* 将包装后的方法记录到缓存中 */
      addEventCache(el, type + '_once', oldHandler, handler);
    }
  
    el.addEventListener(type, handler, capture);
  }
func_documentation_string: 为HTML元素添加事件监听
  @param {HTMLElement} el 目标元素
  @param {String} type 事件名称
  @param {Function} handler 处理函数
  @param {Boolean} once 是否只监听一次
  @param {Boolean|Object} capture 是否在捕获阶段监听，这里也可以传入 { passive: true } 表示被动模式