话不多说，看代码
<!DOCTYPE>
<html>
<head>
<meta charset="UTF-8">
<title>鼠标点击页面中的任意标签，alert该标签的名称</title>
<style>
.box{
height: 100px;
background:red;
}
span{
background:green;
}
p{
background:blue;
}
ul{
background:black;
}
li{
background:yellow;
}
</style>
</head>
<body>
<div class="box">这是div标签
<p>这是div标签里的p标签</p>
<span>这是div标签里的span标签</span>
</div>
<p>这是p标签</p>
<span>这是span标签</span>
<ul>
<li>这是li标签</li>
<li>这是li标签</li>
<li>这是li标签</li>
</ul>
</body>
<script type="text/javascript">
document.onclick = function(e){
var e = window.event || e;
var tag = e["target"] || e["srcElement"];
alert(tag.tagName);
};
</script>
</html>