创建 跨浏览器兼容事件

//事件兼容代码

    var EventUtil = {
      addHandler: function(element, type, handler) {

      },

      getEvent: function(event) {
        return event ? event : window.event;
      },

      getTarget: function(event) {
        return event.target || event.srcElement;
      },

      preventDefault: function(event) {
        if (event.preventDefault) {
          event.preventDefault();
        } else {
          event.returnValue = false;
        }
      },

      removeHandler: function(element, type, handler) {

      },

      stopPropagation: function(event) {
        if (event.stopPropagation) {
          event.stopPropagation();
        } else {
          event.cancelBubble = true;
        }
      }
    }

在《高程3》中的例子