function over(obj) {
  obj.className='navigatiedelen_hover';
}
 
function uit(obj) {
  obj.className='navigatiedelen';
}
<!--

var ico_id;
var el;

var SwapImages = new Array(2);
SwapImages[0] = "img/icon_min.gif";
SwapImages[1] = "img/icon_plus.gif";

for (i in SwapImages)
{
	var LoadImage = new Image();
	LoadImage.src = SwapImages[i]; 
}

function SetButtonImage(name, index) 
{
	document[name].src = SwapImages[index];
}  

function ToggleDiv(id)
{
	var elast;
	div_id = 'antwoord'+id;
	ico_id = 'icon'+id;	

	el = document.getElementById(div_id);
	
	if (el.style.visibility == 'hidden') {
		el.style.position   = 'relative';
		timer = setTimeout("el.style.visibility = 'visible'", 10);
		SetButtonImage (ico_id, 0);
	} else {
		el.style.position   = 'absolute';
		el.style.visibility = 'hidden';
		SetButtonImage (ico_id, 1);
	}
	
	// safari bugfix so we refresh entire html
	elast = document.getElementById('last');
	elast.style.position = (elast.style.position=='absolute')? 'relative': 'absolute';
	return true;
}

-->