var bImagesAvailable = (document.images)?true:false;

if (bImagesAvailable)
{
	var pic = new Array();
	for (i=0;i<30;i++)
	{
	 pic[i] = new Image();
	}
	
	pic[0].src ="images/historieka.jpg";
	pic[1].src ="images/historiekb.jpg";

	pic[2].src ="images/praktischa.gif";
	pic[3].src ="images/praktischb.gif";

	pic[4].src ="images/gemeentea.gif";
	pic[5].src ="images/gemeenteb.gif";
	
	pic[6].src ="images/aktiviteitena.gif";
	pic[7].src ="images/aktiviteitenb.gif";
	
	pic[8].src ="images/scholena.gif";
	pic[9].src ="images/scholenb.gif";
	
	pic[10].src ="images/routea.gif";
	pic[11].src ="images/routeb.gif";
	
	pic[12].src ="images/toeristischa.gif";
	pic[13].src ="images/toeristischb.gif";
	
	pic[14].src ="images/voorstellinga.gif";
	pic[15].src ="images/voorstellingb.gif";
	
	pic[16].src ="images/foruma.gif";
	pic[17].src ="images/forumb.gif";
	
	pic[18].src ="images/linksa.gif";
	pic[19].src ="images/linksb.gif";
	
	pic[20].src ="images/advertentiesa.gif";
	pic[21].src ="images/advertentiesb.gif";
	
	pic[22].src ="images/auteura.gif";
	pic[23].src ="images/auteurb.gif";
}

function rollNav(imgName, imgNumber)
{
	if (bImagesAvailable)
	{
	 document[imgName].src = pic[imgNumber].src;
	}
}