隐藏模态框

1. 判断当前对象

1. IE678：event.srcElement(事件源)
2. 火狐谷歌等：event.target(事件源)

2. 兼容写法获取id

1. var event = event || window.event ;
2. var targettld = event.target ? event.target.id : event.srcElement.id;