SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<ul>
  <li id="a"></li>
  <li id="b"></li>
  <li id="c"></li>
</ul>

JavaScript

alert($('#b').is(":last-child"));
alert($('#c').is(":last-child"));