<script type="text/javascript">
$(function(){
$(":input").focus(function(){
$(this).addClass("focus");
}).blur(function(){
$(this).removeClass("focus");
});
})//这个效果第三个textarea也会添加样式
</script>
<form action="" method="post" id="regForm">
<fieldset>
<legend>个人基本信息</legend>
<div>
<label for="username">名称:</label>
<input id="username" type="text" />
</div>
<div>
<label for="pass">密码:</label>
<input id="pass" type="password" />
</div>
<div>
<label for="msg">详细信息:</label>
<textarea id="msg" rows="2" cols="20"></textarea>
</div>
</fieldset>
</form>