<html><head><script type="text/javascript" src="/jquery/jquery.js"></script><script type="text/javascript">$(document).ready(function(){ $("button").click(function(){ $("p").css("color","red"); });});</script></head><body><p>This is a paragraph.</p><p>This is another paragraph.</p><button type="button">改变段落的颜色</button></body></html>