if (document.images) {
eenon = new Image(); 
eenon.src = "img/menu1_on.gif";

eenoff = new Image(); 
eenoff.src = "img/menu1_off.gif";
}

if (document.images) {
tweeon = new Image(); 
tweeon.src = "img/menu2_on.gif";

tweeoff = new Image(); 
tweeoff.src = "img/menu2_off.gif";
}

if (document.images) {
drieon = new Image(); 
drieon.src = "img/menu3_on.gif";

drieoff = new Image(); 
drieoff.src = "img/menu3_off.gif";
}

if (document.images) {
vieron = new Image(); 
vieron.src = "img/menu4_on.gif";

vieroff = new Image(); 
vieroff.src = "img/menu4_off.gif";
}

if (document.images) {
vijfon = new Image(); 
vijfon.src = "img/menu5_on.gif";

vijfoff = new Image(); 
vijfoff.src = "img/menu5_off.gif";
}

if (document.images) {
zeson = new Image(); 
zeson.src = "img/menu6_on.gif";

zesoff = new Image(); 
zesoff.src = "img/menu6_off.gif";
}

if (document.images) {
zevenon = new Image(); 
zevenon.src = "img/menu7_on.gif";

zevenoff = new Image(); 
zevenoff.src = "img/menu7_off.gif";
}

if (document.images) {
achton = new Image(); 
achton.src = "img/menu8_on.gif";

achtoff = new Image(); 
achtoff.src = "img/menu8_off.gif";
}

if (document.images) {
zoek1on = new Image(); 
zoek1on.src = "img/zoekinfo_on.gif";

zoek1off = new Image(); 
zoek1off.src = "img/zoekinfo_off.gif";
}

if (document.images) {
zoek2on = new Image(); 
zoek2on.src = "img/zoekadviseur_on.gif";

zoek2off = new Image(); 
zoek2off.src = "img/zoekadviseur_off.gif";
}


function imgOn(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "on.src");
}
}

function imgOff(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "off.src");
}
}

// popup

function popUp(URL) 
{
  day = new Date();
  id = day.getTime();
  eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=1,menubar=0,resizable=1,width=460,height=580,left = 320,top = 272');");
}

// check mail

function formCheck(formobj){
	//1) Enter name of mandatory fields
	var fieldRequired = Array("achternaam", "voornaam", "telefoonnummer", "email" );
	//2) Enter field description to appear in the dialog box
	var fieldDescription = Array("Achternaam", "Voornaam", "Telefoonnummer", "E-Mail adres");
	//3) Enter dialog message
	var alertMsg = "De volgende gegevens zijn nog niet ingevuld:\n";
	
	var l_Msg = alertMsg.length;
	
	for (var i = 0; i < fieldRequired.length; i++){
		var obj = formobj.elements[fieldRequired[i]];
		if (obj){
			switch(obj.type){
			case "select-one":
				if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "select-multiple":
				if (obj.selectedIndex == -1){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "text":
			case "textarea":
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			default:
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
			}
		}
	}

	if (alertMsg.length == l_Msg){
		return true;
	}else{
		alert(alertMsg);
		return false;
	}
}

// check mail toevoegen

<!--
function formCheck_toevoegen(formobj){
	//1) Enter name of mandatory fields
	var fieldRequired = Array("url", "provincie", "thema1", "adres", "postcode", "plaats", "email" );
	//2) Enter field description to appear in the dialog box
	var fieldDescription = Array("Website URL", "Regio waarin uw bedrijf actief is", "Specialisme van uw bedrijf", "Adres", "Postcode", "Plaats", "E-Mail adres van uw bedrijf");
	//3) Enter dialog message
	var alertMsg = "De volgende gegevens zijn nog niet ingevuld:\n";
	
	var l_Msg = alertMsg.length;
	
	for (var i = 0; i < fieldRequired.length; i++){
		var obj = formobj.elements[fieldRequired[i]];
		if (obj){
			switch(obj.type){
			case "select-one":
				if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "select-multiple":
				if (obj.selectedIndex == -1){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "text":
			case "textarea":
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			default:
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
			}
		}
	}

	if (alertMsg.length == l_Msg){
		return true;
	}else{
		alert(alertMsg);
		return false;
	}
}
//-->

// check contact

<!--
function formCheck_contact(formobj){
	//1) Enter name of mandatory fields
	var fieldRequired = Array("achternaam", "voornaam", "opmerkingen", "email" );
	//2) Enter field description to appear in the dialog box
	var fieldDescription = Array("Uw achternaam", "Uw voornaam", "Uw opmerkingen", "Uw E-Mail adres");
	//3) Enter dialog message
	var alertMsg = "De volgende gegevens zijn nog niet ingevuld:\n";
	
	var l_Msg = alertMsg.length;
	
	for (var i = 0; i < fieldRequired.length; i++){
		var obj = formobj.elements[fieldRequired[i]];
		if (obj){
			switch(obj.type){
			case "select-one":
				if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "select-multiple":
				if (obj.selectedIndex == -1){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "text":
			case "textarea":
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			default:
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
			}
		}
	}

	if (alertMsg.length == l_Msg){
		return true;
	}else{
		alert(alertMsg);
		return false;
	}
}
//-->