<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
div { margin-left: 43%; }
p { font: 12px/1.5 Tohama; border: 1px solid #1B1B17; width: 19%; background-color: yellow; display: none; }
</style>
<script src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
</head>
<body>
<div>
<form>
<label>
<input type="checkbox">
记住密码
</label>
<p>请不要在公众场合选择此选项。</p>
</form>
</div>
<script type="text/javascript">
$("label").hover(
function(){
$("p").css("display", "block");
},
function(){
$("p").css("display", "none");
})
</script>
</body>
</html>
原文：http://www.cnblogs.com/samtrybest/p/5071446.html