code: function EventDispatcher(target) {
              if (target === void 0) { target = null; }
              /**
               * 冒泡属性名称为“parent”
               */
              this.bubbleAttribute = "parent";
              this.target = target;
              if (this.target == null)
                  this.target = this;
          }
docs: 构建事件适配器
  @param target		事件适配主体