如果不理解可以看下面文章

​如何用js(jq)给html元素标签前面或者后面增加一个元标签

 

<script>
$(document).ready(function(){
var that=$("#body").find("table");
that.wrap('<div class="table-responsive"></div>');
for(var i=0; i<that.length;i++)
{
that.eq(i).addClass("table");
}
});
</script>

完整代码

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Bootstrap 实例 - 响应式表格</title>
<link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>

<div id="body">
<!--table1-->
<table class="table">
<caption>响应式表格布局1</caption>
<thead>
<tr>
<th>产品</th>
<th>付款日期</th>
<th>状态</th>
</tr>
</thead>
<tbody>
<tr>
<td>产品1</td>
<td>23/11/2013</td>
<td>待发货</td>
</tr>
<tr>
<td>产品2</td>
<td>10/11/2013</td>
<td>发货中</td>
</tr>
<tr>
<td>产品3</td>
<td>20/10/2013</td>
<td>待确认</td>
</tr>
<tr>
<td>产品4</td>
<td>20/10/2013</td>
<td>已退货</td>
</tr>
</tbody>
</table>
<!--table2-->
<table class="table">
<caption>响应式表格布局2</caption>
<thead>
<tr>
<th>产品</th>
<th>付款日期</th>
<th>状态</th>
</tr>
</thead>
<tbody>
<tr>
<td>产品1</td>
<td>23/11/2013</td>
<td>待发货</td>
</tr>
<tr>
<td>产品2</td>
<td>10/11/2013</td>
<td>发货中</td>
</tr>
<tr>
<td>产品3</td>
<td>20/10/2013</td>
<td>待确认</td>
</tr>
<tr>
<td>产品4</td>
<td>20/10/2013</td>
<td>已退货</td>
</tr>
</tbody>
</table>

<!--table3-->
<table class="table">
<caption>响应式表格布局3</caption>
<thead>
<tr>
<th>产品</th>
<th>付款日期</th>
<th>状态</th>
</tr>
</thead>
<tbody>
<tr>
<td>产品1</td>
<td>23/11/2013</td>
<td>待发货</td>
</tr>
<tr>
<td>产品2</td>
<td>10/11/2013</td>
<td>发货中</td>
</tr>
<tr>
<td>产品3</td>
<td>20/10/2013</td>
<td>待确认</td>
</tr>
<tr>
<td>产品4</td>
<td>20/10/2013</td>
<td>已退货</td>
</tr>
</tbody>
</table>
</div>
<script>
$(document).ready(function(){
var that=$("#body").find("table");
console.log(that);
console.log(that.length);
//给所有table元素标签外层嵌套一个div标签
that.wrap('<div class="table-responsive"></div>');
for(var i=0; i<that.length;i++)
{
//给所有table元素标签添加一个样式类
that.eq(i).addClass("table");
}
});
</script>
</body>
</html>