Bootstrap 3 - "data-parent" exemple (minimal code)

index.html

<!--
http://stackoverflow.com/questions/19425165/bootstrap-3-accordion-button-toggle-data-parent-not-working
There is a "bug" that makes the accordion dependent on the .panel class when using the data-parent attribute. To workaround it, you can wrap each accordion group in a 'panel' div..
-->

<a data-toggle="collapse" data-parent=".accordion19" href="#collapseOne">Item #1</a>

<a data-toggle="collapse" data-parent=".accordion19" href="#collapseTwo">Item #2</a>

<a data-toggle="collapse" data-parent=".accordion19" href="#collapseThree">Item #3</a>


<div class="accordion19">
 <div class="panel">
    <div id="collapseOne" class="collapse in">
    Lorem Ipsum 1
    </div>
    <div id="collapseTwo" class="collapse">
    Lorem Ipsum 2
    </div>

</div>
</div>

<div class="accordion19">
 <div class="panel">
    <div id="collapseThree" class="collapse">
    Lorem Ipsum 3
    </div>
</div>
</div>