IE: Object doesn't support property or method 'closest'
<p>I am getting "Object doesn't support property or method 'closest'" error in IE. I am using MooTools. Can anyone help me..</p>

<pre><code>var li = $$('.list')[0].clone(true, true);

var NewContainer = li.getElement('div.tile');

NewContainer.removeProperty('style');

NewContainer.set('id', 'container_'+catId);

NewContainer.closest('li').set('id', 'list_'+countID);
</code></pre>