rm>
Observe page responsiveness:
<br/><br/>
<table><tr>
<td valign="top">
CSS:<br/><div id="loading"></div>
</td>
<td>&nbsp;</td>
<td valign="top">
JavaScript:<br/><div id="time"></div>
</td>
</tr></table>
(JavaScript will stop updating during the hang)
</body>
</html>
