This handler is used by javascript /vsos/vsos.js API.
Include the javascript API in your App HTML files like this :
<script type="text/javascript" src="/tools/jquery.js"></script>
<script type="text/javascript" src="/vsos/vsos.js"></script>
<script type="text/javascript">
//<![CDATA[
VSOS.SetDebug(true);
VSOS.MeasureStart("test");
VSOS.Log("Eh ! This is a javascript Log in the web server logs ! I will stop the screensaver if it is running now...");
VSOS.ScreenSaverStop();
VSOS.Log("It is done now !");
VSOS.MeasureStop("test");
//]]>
</script>