SO fiddle
Test Fiddle mainly for SO Questions
by Nick Craver
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<form>
<input type="text" />
</form>
JavaScript
alert($("input")[0] == document.activeElement);
$("input").focus();
alert($("input")[0] == document.activeElement);