<!DOCTYPE htm>

<meta charset="utf-8">

<meta name="viewport" content="width=device-width, initial-scale=1.0">

<link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">

<style>body {margin:20px}</style>

<button type="button" class="btn btn-primary" data-toggle="collapse" 

    data-target="#demo">

    简单的可折叠组件

</button>    

<div id="demo" class="collapse in">只要用心为用户挖掘想要的功能，这些不谋而合的想法就会不断出现

</div>

<script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.js"></script>

<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

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