var maxDiv='1';

var zichtbaar='1';
function showmenu(welke,zien){
	if(document.getElementById){
		if(zien == '0' && zichtbaar != '1'){
			for(i=1; i<=maxDiv; i++){
				document.getElementById('nav'+i).style.visibility = 'hidden';
				document.getElementById('nav'+i).style.display = 'none';
			}
		}else{
			field = document.getElementById(welke);
			for(i=1; i<=maxDiv; i++){
					document.getElementById('nav'+i).style.visibility = 'hidden';
					document.getElementById('nav'+i).style.display = 'none';
			}
			field.style.visibility = 'visible';
			field.style.display = 'block';
			zichtbaar = '1';
			clearTimeout(vertraging);
		}
	}else if (document.all){
		if (zien == '0' && zichtbaar != '1'){
			for (i=1; i<=maxDiv; i++){
				document.all['nav'+i].style.visibility = 'hidden';
				document.all['nav'+i].style.display = 'none';
			}
		}else{
			field = document.all[welke]
			for (i=1; i<=maxDiv; i++){
				document.all['nav'+i].style.visibility = 'hidden';
				document.all['nav'+i].style.display = 'none';
			}
			field.style.visibility = 'visible';
			field.style.display = 'inline';
			zichtbaar = '1';
			clearTimeout(vertraging);
		}
	}else if (document.layers){
		if(zien == '0' && zichtbaar != '1'){
			for (i=1; i<=maxDiv; i++){
				document.layers['nav'+i].style.visibility = 'hidden';
				document.layers['nav'+i].style.display = 'none';
			}
		}else{
			field = document.all[welke]
			for (i=1; i<=maxDiv; i++){
				document.layers['nav'+i].style.visibility = 'hidden';
				document.layers['nav'+i].style.display = 'none';
			}
			field.style.visibility = 'visible';
			field.style.display = 'inline';
			zichtbaar = '1';
			clearTimeout(vertraging);
		}
	}
}
var vertraging;
function hidemenu(tmp){
	zichtbaar = '0';
	tmp2 = tmp;
	vertraging = setTimeout('showmenu(tmp2,\'0\')',0200);
}