demo82.html

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>jquery实现tab栏目切换</title>
	<style>
		span{
			display: inline-block;
			width: 50px;
			text-align: center;
			cursor: pointer;
		}
		.selected{
			color: red;
		}
		p{
			display: none;
		}
		.show{
			display: block;
		}
	</style>
</head>
<body>
	<div id="tab">
		<span class="selected">1</span>
		<span>2</span>
		<span>3</span>
	</div>
	<div id="content">
		<p class="show">a</p>
		<p>b</p>
		<p>c</p>
	</div>
	
	<script src="js/jquery.js"></script>
	<script type="text/javascript">
		$(function () {
			$("#tab span").click(function () {
				var i = $(this).index();// 下标第一种写法
	            // var i = $("#tab span").index(this);// 下标第二种写法
				$(this).addClass("selected").siblings().removeClass("selected");
				$("#content p").eq(i).show().siblings().hide();
			});
		});
	</script>
</body>
</html>