function showNavOptions(optionName){
	
	document.getElementById('row1_1').style.visibility = "hidden";
	document.getElementById('row1_2').style.visibility = "hidden";
	document.getElementById('row1_3').style.visibility = "hidden";
	document.getElementById('row1_4').style.visibility = "hidden";

	document.getElementById('row2_1').style.visibility = "hidden";
	document.getElementById('row2_2').style.visibility = "hidden";
	document.getElementById('row2_3').style.visibility = "hidden";
	document.getElementById('row2_4').style.visibility = "hidden";

	document.getElementById('row3_1').style.visibility = "hidden";
	document.getElementById('row3_2').style.visibility = "hidden";
	document.getElementById('row3_3').style.visibility = "hidden";
	document.getElementById('row3_4').style.visibility = "hidden";

	document.getElementById('row4_1').style.visibility = "hidden";
	document.getElementById('row4_2').style.visibility = "hidden";
	document.getElementById('row4_3').style.visibility = "hidden";
	document.getElementById('row4_4').style.visibility = "hidden";

	document.getElementById('row5_1').style.visibility = "hidden";
	document.getElementById('row5_2').style.visibility = "hidden";
	document.getElementById('row5_3').style.visibility = "hidden";
	document.getElementById('row5_4').style.visibility = "hidden";

	document.getElementById('row1_5').style.visibility = "hidden";
	document.getElementById('row2_5').style.visibility = "hidden";
	document.getElementById('row3_5').style.visibility = "hidden";
	document.getElementById('row4_5').style.visibility = "hidden";
	document.getElementById('row5_5').style.visibility = "hidden";

	if(optionName=='home')
	{
		document.getElementById('sub1').style.visibility = "hidden";
		document.getElementById('sub2').style.visibility = "hidden";
		document.getElementById('sub3').style.visibility = "hidden";
		document.getElementById('sub4').style.visibility = "hidden";
		document.getElementById('sub5').style.visibility = "hidden";
	}

	if(optionName=='graf')
	{
		document.getElementById('sub1').style.visibility = "visible";
		document.getElementById('sub2').style.visibility = "visible";
		document.getElementById('sub3').style.visibility = "visible";
		document.getElementById('sub4').style.visibility = "visible";
		document.getElementById('sub5').style.visibility = "visible";

		document.getElementById('row1_2').style.visibility = "visible";
		document.getElementById('row2_2').style.visibility = "visible";
		document.getElementById('row3_2').style.visibility = "visible";
		document.getElementById('row4_2').style.visibility = "visible";
		document.getElementById('row5_2').style.visibility = "visible";
	}

	if(optionName=='bouw')
	{
		document.getElementById('sub1').style.visibility = "visible";
		document.getElementById('sub2').style.visibility = "hidden";
		document.getElementById('sub3').style.visibility = "hidden";
		document.getElementById('sub4').style.visibility = "hidden";
		document.getElementById('sub5').style.visibility = "hidden";

		document.getElementById('row1_3').style.visibility = "visible";
	}

	if(optionName=='urn')
	{
		document.getElementById('sub1').style.visibility = "visible";
		document.getElementById('sub2').style.visibility = "hidden";
		document.getElementById('sub3').style.visibility = "hidden";
		document.getElementById('sub4').style.visibility = "hidden";
		document.getElementById('sub5').style.visibility = "hidden";

		document.getElementById('row1_5').style.visibility = "visible";
	}

	if(optionName=='bouw2')
	{
		document.getElementById('sub1').style.visibility = "visible";
		document.getElementById('sub2').style.visibility = "visible";
		document.getElementById('sub3').style.visibility = "visible";
		document.getElementById('sub4').style.visibility = "hidden";
		document.getElementById('sub5').style.visibility = "hidden";

		document.getElementById('row1_4').style.visibility = "visible";
		document.getElementById('row2_4').style.visibility = "visible";
		document.getElementById('row3_4').style.visibility = "visible";
	}

}

if (document.images) {
	nav_home = new Image();
	nav_home.src = "img/btn_home.gif";
	nav_homeover = new Image();
	nav_homeover.src = "img/btn_home2.gif";
	
	nav_graf = new Image();
	nav_graf.src = "img/btn_grafwerk.gif";
	nav_grafover = new Image();
	nav_grafover.src = "img/btn_grafwerk2.gif";
	
	nav_bouw = new Image();
	nav_bouw.src = "img/btn_bouwwerk.gif";
	nav_bouwover = new Image();
	nav_bouwover.src = "img/btn_bouwwerk2.gif";
	
	nav_urn = new Image();
	nav_urn.src = "img/btn_urn.gif";
	nav_urnover = new Image();
	nav_urnover.src = "img/btn_urn2.gif";

	nav_bouw2 = new Image();
	nav_bouw2.src = "img/Xbtn_bouwwerk.gif";
	nav_bouw2over = new Image();
	nav_bouw2over.src = "img/Xbtn_bouwwerk2.gif";
	
	nav_adres = new Image();
	nav_adres.src = "img/btn_adres.gif";
	nav_adresover = new Image();
	nav_adresover.src = "img/btn_adres2.gif";
	
	nav_route = new Image();
	nav_route.src = "img/btn_route.gif";
	nav_routeover = new Image();
	nav_routeover.src = "img/btn_route2.gif";
}
	
	
function swapOn(imgName) {
	if (document.images) {
	eval("document." + imgName + ".src = " + imgName + "over.src");
	}
}

function swapOff(imgName) {
	if (document.images) {
	eval("document." + imgName + ".src = " + imgName + ".src");
	}
}

function selectRowOn(id) {
	document.getElementById(id).style.border='1px solid #D0D5DA';
}

function selectRowOff(id) {
	document.getElementById(id).style.border='1px solid #7683AF';
}
function go(field)
{
	parent.main.location.href="main.php?field="+field;
}