<body onclick="alert(1)">
<div id="app" onclick="alert(10)">
<p onclick="alert(100)">一个p标签</p>
</div>
<script>
var p = document.getElementsByTagName("p")[0];
p.onclick = function (event){
alert(100);
// 阻止冒泡
event.stopPropagation();
};
var app = document.getElementById("app");
app.onclick = function (event){
alert(10);
event.stopPropagation();
}
var body = document.body;
body.onclick = function (){
alert(1);
}
</script>