<html><head><script type="text/javascript" src="/jquery/jquery.js"></script><script type="text/javascript">$(document).ready(function(){ $(".btn1").click(function(){ $("p").before("<p>Hello world!</p>"); });});</script></head><body><p>This is a paragraph.</p><button class="btn1">在每个段落前面插入新的段落</button></body></html>