How to get button groups that span the full width of a parent in Bootstrap? : <p>In Bootstrap, how can I get a button group like the following that span the full width of a parent element? (like with the ".btn-block" class, but applied to a group <a href="http://getbootstrap.com/css/#buttons-sizes" rel="noreferrer">http://getbootstrap.com/css/#buttons-sizes</a> )</p>

<pre><code>&lt;div class="btn-group" role="group" aria-label="..."&gt;
  &lt;button type="button" class="btn btn-default"&gt;Left&lt;/button&gt;
  &lt;button type="button" class="btn btn-default"&gt;Middle&lt;/button&gt;
  &lt;button type="button" class="btn btn-default"&gt;Right&lt;/button&gt;
&lt;/div&gt;
</code></pre>
