Jquery on focus event delegation
<p>For some strange reason this simple function doesn't seem to work:</p>

<pre><code>$("body").on("focus", this, function(){
    alert('d');
})
</code></pre>

<p><code>this</code> is input or textarea element.</p>

<p>If i were to do this:</p>

<pre><code>$(this).on("focus", function(){
    alert('d');
})
</code></pre>

<p>It would work on those elements that exists at the moment, but i event would not fire up on newly created elements, what am i doing wrong?</p>
