jQuery can't get .closest() to search up DOM tree
<p><a href="http://jsfiddle.net/3Bvt9/3/" rel="nofollow">http://jsfiddle.net/3Bvt9/3/</a></p>

<p>HTML</p>

<pre><code>&lt;div id="div1"&gt;
    &lt;img class="size" src=""&gt;
    &lt;input name="rdo" id="rdo" type="radio" value="1"&gt;
        &lt;div id="div2"&gt;
            &lt;label&gt;radiobutton&lt;/label&gt;
            &lt;div id="div3"&gt;
                &lt;a href="javascript:void(0)"&gt;link&lt;/a&gt;
                &lt;input name="abc" id="abc" type="hidden" value="1"&gt;
            &lt;/div&gt;
        &lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p>jquery</p>

<pre><code>$('#abc').parent().parent().parent().find("input[type='radio']").length; //1
$('#abc').closest("input[type='radio']").length; //0 why?
</code></pre>

<p>Why doesn't the closest query work? I thought closest() traverses up through its ancestors in the DOM tree.</p>
