利用事件的冒泡特性，为子标签添加Onclick事件

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
    <script type="text/javascript">
        window.onload = function () {
            var list = document.getElementById("myLinks");
            list.onclick = function (event) {
                var target = event.target;
                switch (target.id) {
                    case "doSomething":
                        document.title = "I change the document's title";
                        break;
                    case "goSomewhere":
                        location.href = "http://baidu.com";
                        break;
                    case "sayHi":
                        alert("hi");
                        break;
                }
            }
        }

    </script>
</head>
<body>
    <ul id="myLinks">
        <li id="goSomewhere">Go somewhere</li>
        <li id="doSomething">Do something</li>
        <li id="sayHi">Say hi</li>
    </ul>
</body>
</html>

这样的好处是，不需要为3个li 增加Onclick事件，从而节约内存