<html><head><script type="text/javascript" src="/jquery/jquery.js"></script><script type="text/javascript">$(document).ready(function(){ $("button").click(function(){ $("p").before(function(n){ return "<p>The p element below has index " + n + "</p>"; }); });});</script></head><body><h1>This is a heading</h1><p>This is a paragraph.</p><p>This is another paragraph.</p><button class="btn1">在每个段落前面插入新的段落</button></body></html>