jQuery .each callback error
<p>I am currently messing with the <code>.each()</code> function in jQuery and I am trying to count all <code>div</code>'s with the the <code>id</code> of item and add them to a string.</p>

<p>The problem is, I get a callback error from my jQuery source, which I load from jquery.com's website.</p>

<pre><code>var items = "";
$('div.item').each(function(){ 
    items += $('this').data('id');
});
</code></pre>

<p>The error, as seen on firebug;</p>

<pre><code>callback is undefined
if ( callback.call( object[ i ], i, object[ i++ ] ) === false ) { 
</code></pre>
