var random_display = 1; // 0 = sequential, 1 = random
var new_image =""
var image_index = 0;
var image_index_l = 0;
// afbeeldingen groot (h)
image_list = new Array();
image_list[image_index++] = new imageItem("images/statiqcooler_bg_h1.jpg");
image_list[image_index++] = new imageItem("images/statiqcooler_bg_h2.jpg");
image_list[image_index++] = new imageItem("images/statiqcooler_bg_h3.gif");
image_list[image_index++] = new imageItem("images/statiqcooler_bg_h4.gif");
var number_of_image = image_list.length;

image_list_l = new Array();
image_list_l[image_index_l++] = new imageItem("images/statiqcooler_bg_l1.jpg");
image_list_l[image_index_l++] = new imageItem("images/statiqcooler_bg_l2.gif");

var number_of_image_l = image_list_l.length;


function imageItem(image_location) {
this.image_item = new Image();
this.image_item.src = image_location;
}

function get_ImageItemLocation(imageObj) {
return(imageObj.image_item.src)
}

function getNextImage() {
if (random_display) {
image_index = generate(0, number_of_image-1);
//alert('image_index= ' +image_index)
}
else {
image_index = (image_index+1) % number_of_image;
}
var new_image = get_ImageItemLocation(image_list[image_index]);
return(new_image);
}


function rotateImage(place) {
	new_image ='<div id="header" style="background-image:url('+getNextImage()+')">'
}

//afbeeldingen klein (l)
function imageItem_l(image_location) {
this.image_item = new Image();
this.image_item.src = image_location;
}

function get_ImageItemLocation_l(imageObj) {
return(imageObj.image_item.src)
}

function getNextImage_l() {
if (random_display) {
image_index_l = generate(0, number_of_image_l-1);
//alert('image_index_l= ' +image_index_l)
}
else {
image_index_l = (image_index_l+1) % number_of_image_l;
}
var new_image = get_ImageItemLocation_l(image_list_l[image_index_l]);
return(new_image);
}

function rotateImage_l(place) {
	new_image ='<div id="header_l" style="background-image:url('+getNextImage_l()+')">'
}

function generate(x, y) {
var range = y - x + 1;
return Math.floor(Math.random() * range) + x;
}


sfHover = function() {
	var sfEls = document.getElementById("nav").getElementsByTagName("LI");
	for (var i=0; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
			this.className+=" sfhover";
		}
		sfEls[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp(" sfhover\\b"), "");
		}

	}
}
if (window.attachEvent) window.attachEvent("onload", sfHover);


<!-- zichtbaarheid blokje hoofdlevel navigatie -->
function toggleDiv(id,flagit) {
if (flagit=="1"){
if (document.layers) document.layers[''+id+''].visibility = "show"
else if (document.all) document.all[''+id+''].style.visibility = "visible"
else if (document.getElementById) document.getElementById(''+id+'').style.visibility = "visible"
}
else
if (flagit=="0"){
if (document.layers) document.layers[''+id+''].visibility = "hide"
else if (document.all) document.all[''+id+''].style.visibility = "hidden"
else if (document.getElementById) document.getElementById(''+id+'').style.visibility = "hidden"
}
}

function navblk() {
var sfElsli = document.getElementById("nav").getElementsByTagName("LI");
for (var i=0; i<sfElsli.length; i++) {
//alert(i)	
		sfElsli[i].onmouseover=function() {
			this.className=this.className.replace(new RegExp(" sfhover\\b"), "");
		}
		

	}
}

function checkFormSC(form) {
inputStr= form.question.value
if (inputStr == "") { alert(" U hebt uw vraag of opmerking nog niet ingevoerd "); return false } 
inputStr= form.fname.value
if (inputStr == "") { alert(" U hebt uw voorletters nog niet ingevoerd "); return false } 
inputStr= form.lname.value
if (inputStr == "") { alert(" U hebt uw naam nog niet ingevoerd "); return false } 
inputStr= form.company.value
if (inputStr == "") { alert(" U hebt uw bedrijfsnaam nog niet ingevoerd "); return false }  

inputStr= form.address.value
if (inputStr == "") { alert(" U hebt uw adres nog niet ingevoerd "); return false }  
//postcode
inputStr= form.zip.value
if (inputStr == "") { alert(" U hebt uw postcode nog niet ingevoerd "); return false }
if (inputStr != "" && inputStr.length < 6) { alert("U hebt uw postcode niet juist, of niet volledig ingevuld "); return false }
else{
for (i=0; i<inputStr.length-2; i++) {
var oneChar = inputStr.substring(i, i+1)
if(oneChar <"0" || oneChar >"9") { alert(" Uw postcode is onjuist ingevoerd ") }
for (i=4; i<inputStr.length; i++) {
var oneChar = inputStr.substring(i, i+1)
if (oneChar >= "0" && oneChar <= "9") {
alert(" Uw postcode is onjuist ingevoerd ")
return false
}
}
}
}
//woonplaats
inputStr= form.state.value
if (inputStr == "") { alert(" U hebt geen landnaam ingevoerd "); return false }
inputStr= form.city.value
if (inputStr == "") { alert(" U hebt uw woonplaats nog niet ingevoerd "); return false }
//telefoon
inputStr= form.telephone.value
if (inputStr == "" || inputStr == "*") { alert(" U hebt uw telefoonnummer nog niet ingevoerd "); return false } 
if (inputStr.length < 8) {
alert(" Het telefoonnummer is niet correct ")
return false
}
else {
for (i=0; i<inputStr.length; i++) {
var oneChar = inputStr.substring(i, i+1)
if (oneChar < "0" || oneChar > "9") {
if (oneChar != "-" && oneChar != "+" && oneChar != "(" && oneChar != ")" ) {
alert(" Het telefoonnummer is niet correct. ")
return false
}
}
}
}
inputStr= form.email.value
if (inputStr == "") { alert(" U hebt uw e-mailadres nog niet ingevoerd "); return false }
else {
if (inputStr.indexOf("@") == -1 || inputStr.indexOf(".") == -1 || inputStr.indexOf(" ") != -1) {
alert(" Het e-mailadres is niet correct. ")
return false
}
}


}

function checkFormSC_e(form) {

if (form.username){
inputStr= form.username.value
if (inputStr == "") { alert("Please enter a user name"); return false } 
}
if (form.question){
inputStr= form.question.value
if (inputStr == "") { alert("Please enter your question or remark"); return false } 
}
if (form.fname){
inputStr= form.fname.value
if (inputStr == "") { alert("Please enter your first name"); return false } 
}
if (form.lname){
inputStr= form.lname.value
if (inputStr == "") { alert("Please enter your last name"); return false } 
}
if (form.company){
inputStr= form.company.value
if (inputStr == "") { alert("Please enter your company's name"); return false }
}
if (form.address){
inputStr= form.address.value
if (inputStr == "") { alert("Please enter your address"); return false }  
}
//postcode
if (form.zip){
inputStr= form.zip.value
if (inputStr == "") { alert("Please enter your zip code"); return false }
}
//if (inputStr != "" && inputStr.length < 6) { alert("U hebt uw postcode niet volledig ingevuld"); return false }
//else{
//for (i=0; i<inputStr.length-2; i++) {
//var oneChar = inputStr.substring(i, i+1)
//if(oneChar <"0" || oneChar >"9") {
//alert(" Uw postcode is onjuist ingevoerd")
//return false
//}
//}
//for (i=4; i<inputStr.length; i++) {
//var oneChar = inputStr.substring(i, i+1)
//if (oneChar >= "0" && oneChar <= "9") {
//alert(" Uw postcode is onjuist ingevoerd")
//return false
////}
//}
//}
//woonplaats
if (form.state){
inputStr= form.state.value
if (inputStr == "") { alert("Please enter your state"); return false }
}
if (form.city){
inputStr= form.city.value
if (inputStr == "") { alert("Please enter your city"); return false }
}
//telefoon
if (form.telephone){
inputStr= form.telephone.value
if (inputStr == "" || inputStr == "*") { alert("Please enter your phone number"); return false } 
if (inputStr.length < 8) {
alert(" Please enter a valid phone number ")
return false
}
else {
for (i=0; i<inputStr.length; i++) {
var oneChar = inputStr.substring(i, i+1)
if (oneChar < "0" || oneChar > "9") {
if (oneChar != "-" && oneChar != "+" && oneChar != "(" && oneChar != ")" ) {
alert(" Please enter a valid your phone number ")
return false
}
}
}
}
}
if (form.email){
inputStr= form.email.value
if (inputStr == "") { alert(" Please enter your E-mail address"); return false }
else {
if (inputStr.indexOf("@") == -1 || inputStr.indexOf(".") == -1 || inputStr.indexOf(" ") != -1) {
alert(" Please enter a valid E-mail address ")
return false
}
}
}

}