1、例子：
<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("button").click(function(){
$("li").each(function(){
alert($(this).text())
});
});
});
</script>
</head>
<body>
<button>输出每个列表项的值</button>//点击此button的文本值会弹出带有Coffee文本值的、再点击弹出Milk、再点击弹出Soda
<ul>
<li>Coffee</li>
<li>Milk</li>
<li>Soda</li>
</ul>
</body>
</html>