tmr = 0;
	
	function show_sub() {
		window.clearTimeout(tmr);
		document.getElementById('subnav_knop1').style.visibility = 'visible';
	}
	
	function hide_sub() {
		document.getElementById('subnav_knop1').style.visibility = 'hidden';
	}
	
	
				function resetTimer()
				{
					window.clearTimeout(tmr);
					tmr = window.setTimeout("hide_sub()",1000)
				}
		
				function stopTimer()
				{
					window.clearTimeout(tmr);
				}
		
				function startTimer()
				{
					tmr = window.setTimeout("hide_sub()",1000)
				}