冒泡

一层一层往上找～～
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name='viewport' , content='width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no' />
    <title>center</title>
    <style>
        body,
        p,
        div {
            margin: 0;
            padding: 0;
            font-size: 16px;
        }

        .small1 {
            width: 100px;
            height: 100px;
            background: #ccc;
            position: absolute;
            z-index: 3;
        }

        .small2 {
            width: 200px;
            height: 100px;
            background: #f0f;
            position: absolute;
            z-index: 2;
        }

        .small3 {
            width: 300px;
            height: 100px;
            background: #ff5555;
            position: absolute;
            z-index: 1;
        }

        .middle {
            width: 100px;
            height: 200px;
            background: #666;
        }

        .big {
            width: 100px;
            height: 300px;
            background: #333;
        }
    </style>
</head>

<body>
    <div class='big'>
        <div class='middle'>
            <div class='small1'></div>
            <div class='small2'></div>
            <div class='small3'></div>
        </div>
    </div>
</body>
<script src='//cdn.bootcss.com/jquery/3.0.0/jquery.min.js'></script>
<script>
    $('.small1,.small2,.small3').click(function(event) {
        // event.stopPropagation(); 方法一
        alert('aaa');
        return false;// 方法二
    });
    $('.middle').click(function() {
        alert('bbb');
    });
    $('.big').click(function() {
        alert('ccc');
    })
</script>

</html>
只有子集、父级的情况有冒泡，兄弟级没有哦。