function keep_alive()
{
	var ajax	= new sack();

	var theTime	= new Date();
	var theTime	= theTime.getTime();

	ajax.setVar( "time", theTime );

	ajax.requestFile	= "ajax/keep_alive.php";
	ajax.method			= "GET";
	ajax.element		= "keep_alive";
	ajax.onCompletion	= finishKeepAlive;
	
	ajax.runAJAX();
}

function finishKeepAlive()
{
	setTimeout( 'keep_alive()', 90 * 1000 );
}

finishKeepAlive();