<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$(".btn1").click(function(){
$("p").toggle(true);
});
});
</script>
</head>
<body>
<p>This is a paragraph.</p>
<p style="display:none">This is another paragraph.</p>
<p>把 switch 参数设置为 false,可以隐藏所有段落。</p>
<button class="btn1">显示所有 p 元素</button>
</body>
</html>