:input表示选择表单中的input,select,textarea,button元素，input仅仅选择input元素。
<html> <head> <style> .focus{ background-color: blue } </style> </head> <body> <script type="text/javascript" src="scripts/jquery.1.6.1.min.js"></script> <script type="text/javascript"> $(function(){ $(":input").focus(function(){ $(this).addClass("focus"); }).blur(function(){ $(this).removeClass("focus"); }); }) </script> <form action="" method="post" id="regForm"> <fieldset> <legend>Personal Info</legend> <div> <label for="username">Name:</label> <input id="username" type="text" /> </div> <div> <label for="pass">Password:</label> <input id="pass" type="password" /> </div> <div> <label for="msg">Detail Information:</label> <textarea id="msg" rows="2" cols="20"></textarea> </div> <div> <select name="single"> <option>Single</option> <option>Single2</option> </select> </div> <div> <select name="multiple" multiple="multiple"> <option selected="selected">Multiple</option> <option>Multiple2</option> <option selected="selected">Multiple3</option> </select> </div> </fieldset> </body> </html>
http://www.jb51.net/article/27688.htm
原文：http://www.cnblogs.com/hellolong/p/4019393.html