Refresh widget doesn't work


I’m trying to refresh my own randomNumber widget when clicking on an area, but doesn’t work.
I tried as it’s indicated in the FAQ but it didn’t work.

This is my example code in the Controller.php file…

class Piwik_EXAMPLE_Controller extends Piwik_Controller
    function randomNumber()
        echo "	<SCRIPT LANGUAGE='javascript'>
					function refreshRandom()
//						$(this).parents('[widgetEXAMPLEconcurrentUsers]').dashboardWidget('reload');


    			<p onclick=\"refreshRandom()\">Click this text to refresh!!!.</p>";

        echo "<p><center><H1>".rand(0 ,5000)." randomNumber</H1></center></p>";

Thanks and regards.