51help TIY
码：
<html> <head> <script type="text/javascript" src="../jquery/jquery.js" tppabs="http://www.51help.tk/jquery/jquery.js"></script> <script type="text/javascript"> $(document).ready(function(){ $("button").click(function(){ $('p').addClass(function(n){ return 'par_' + n; }); }); }); </script> <style type="text/css"> .par_0 { color:blue; } .par_1 { color:red; } </style> </head> <body> <h1>This is a heading</h1> <p>This is a paragraph.</p> <p>This is another paragraph.</p> <button>向 p </button> </body> </html>
查看结果: