// HANDLE WINDOW.ONLOAD:s ---------------------------------------------------- 
 
if (document.getElementById && document.getElementsByTagName && document.createTextNode) { 
	window.onload = init; 
} 
 
var onLoads = new Array; 

function init() { 
	for (var i = 0; i < onLoads.length; i++) {  
	eval(onLoads[i]); 
	} 
} 
 
function addOnLoad(func) { 
	onLoads[onLoads.length] = func; 
}

addOnLoad("checkLinks()");
addOnLoad("browseImages()");
addOnLoad("hoverText()");
addOnLoad("lightFirstAvailCampaing()");

function checkLinks(){
	var lnks = document.getElementsByTagName("a");
	for(var i=0;i<lnks.length;i++){
		if(lnks[i].className == "extLnk") {
			lnks[i].target = "_blank";
		}
	}
}
var imgArray = new Array();
var lnkArray = new Array();
var altArray = new Array();
function browseImages() {
	
	var arrLength = imgArray.length - 1; 
	var currItem = 0; 
	if(document.getElementById("arrowleft")) {
		arrow1 = document.getElementById("arrowleft");
		arrow2 = document.getElementById("arrowright");
		arrow1.onclick = stepImgBack;
		arrow2.onclick = stepImgFor;
	}
}

function stepImgFor(){  
	
	if(currItem <arrLength){
		currItem++; 
	}else if(currItem == arrLength) {  
		currItem = 0;  
	}
	document.getElementById("lnkCampaign").href = lnkArray[currItem];
	document.getElementById("imgCampaign").src = imgArray[currItem]; 
	document.getElementById("imgCampaign").alt = altArray[currItem]; 
	
	return false;
}

function stepImgBack(){  

	if(currItem == 0){ 
		currItem = arrLength;
	}else { 
		currItem--; 
	}
	document.getElementById("lnkCampaign").href = lnkArray[currItem];
	document.getElementById("imgCampaign").src = imgArray[currItem];
	document.getElementById("imgCampaign").alt = altArray[currItem];
		
	return false;
}

function hoverText() {
	var iconArray = new Array();
	iconArray[0] = "icon1";
	iconArray[1] = "icon2";
	iconArray[2] = "icon3";
	iconArray[3] = "icon4";
	
	for(var i=0;i<iconArray.length;i++) {
		
		if ( document.getElementById(iconArray[i]) != null ) {
			document.getElementById(iconArray[i]).onmouseover = showText;
			document.getElementById(iconArray[i]).onmouseout = hideText;
		}
	}
}

function showText() {
	obj = document.getElementById("hoverText");
	obj.style.display = "block";
}

function hideText() {
	obj = document.getElementById("hoverText");
	obj.style.display = "none";
}

<!-- sets the first avalible picture in the campaing div -->	 
function lightFirstAvailCampaing(){
	if (lnkArray.length > 0) {
		document.getElementById("lnkCampaign").href = lnkArray[0];
		document.getElementById("imgCampaign").src  = imgArray[0];
		document.getElementById("imgCampaign").alt  = altArray[0];
	}
}