<html><head><script type="text/javascript" src="/jquery/jquery.js"></script><script type="text/javascript">$(document).ready(function(){$(".btn1").click(function(){ $("p").empty(); });});</script></head><body><p style="width:200px;height:200px;background-color:yellow">This is a paragraph. <b>Bold</b> and <i>italic</i> text.</p><button class="btn1">删除 p 元素的内容</button></body></html>