下面是闭包做选项卡：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>闭包做选项卡</title>
<style type="text/css">
.btns{
500px;
height:50px;
}
.btns input{
100px;
height:50px;
background-color: #ddd;
color:#666;
border:0;
}
.btns input.cur{
background-color: gold;
}
.contents div{
500px;
height:300px;
background-color: gold;
display: none;
line-height:300px;
text-align: center;
}
.contents div.active{
display: block;
}
</style>
<script type="text/javascript">
window.onload = function(){
var aBtn = document.getElementById('btns').getElementsByTagName('input');
var aContent = document.getElementById('contents').getElementsByTagName('div');
//用闭包存起来，这个i就有1，2，3这个值了，不过实际中不这样用，小题大做了
for(var i=0;i<aBtn.length;i++){
(function (i) {
aBtn[i].onclick = function () {
for(var j=0;j<aBtn.length;j++){
aBtn[j].className = '';
aContent[j].className = '';
}
this.className = 'cur';
aContent[i].className = 'active';
}
})(i)
}
}
</script>
</head>
<body>
<div class="btns" id="btns">
<input type="button" value="tab01" class="cur">
<input type="button" value="tab02">
<input type="button" value="tab03">
</div>
<div class="contents" id="contents">
<div class="active">tab文字内容一</div>
<div>tab文字内容二</div>
<div>tab文字内容三</div>
</div>
</body>
</html>
jquery库做选项卡：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>js库做选项卡</title>
<script type="text/javascript" src="jquery-1.12.4.min.js"></script>
<style type="text/css">
.btns{
500px;
height:50px;
}
.btns input{
100px;
height:50px;
background-color: #ddd;
color:#666;
border:0;
}
.btns input.cur{
background-color: gold;
}
.contents div{
500px;
height:300px;
background-color: gold;
display: none;
line-height:300px;
text-align: center;
}
.contents div.active{
display: block;
}
</style>
<script type="text/javascript">
$(function () {
$('#btns input').click(function(){
//this是原生的对象
$(this).addClass('cur').siblings().removeClass('cur');
//alert($(this).index())弹出索引值
$('#contents div').eq($(this).index()).addClass('active').
siblings().removeClass('active')
})
})
</script>
</head>
<body>
<div class="btns" id="btns">
<input type="button" value="tab01" class="cur">
<input type="button" value="tab02">
<input type="button" value="tab03">
</div>
<div class="contents" id="contents">
<div class="active">tab文字内容一</div>
<div>tab文字内容二</div>
<div>tab文字内容三</div>
</div>
</body>
</html>