js——事件冒泡与捕获小例子

#outer{
    width: 300px;
    height: 300px;
    background: red;
}
#inner{
    width: 200px;
    height: 200px;
    background: green;
}

<div id="outer">
    <div id="inner"></div>
</div>

var inner = document.getElementById("inner");
var outer = document.getElementById("outer");
inner.addEventListener("click", function(e){
    alert("inner");
}, true);
outer.addEventListener("click", function(e){
    alert("outer");
}, true);
document.addEventListener("click", function(e){
    alert("document");
}, true);