JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.1/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.1/css/bootstrap-combined.min.css">
<div class="row-fluid summary">
    <div class="span11">
        <h2>MyHeading</h2>  
    </div>
    <div class="span1">
        <input type="button" id="collapsible" class="btn btn-success" data-toggle="collapse" data-target="#intro" value="+"></input>
    </div>
</div>
<div class="row-fluid summary">
    <div id="intro" class="collapse"> 
        Here comes the text...
    </div>
</div>

CSS

#collapsible
{
    width:35px;
}

JavaScript

function handleClick()
{
    this.value = (this.value == '+' ? '-' : '+');
}
document.getElementById('collapsible').onclick=handleClick;