//the next 3 lines are browser detection for user-agent DOMS
ns4 = (document.layers) ? true:false //required for Functions to work
ie4 = (document.all) ? true:false //required for Functions to work
ng5 = (document.getElementById) ? true:false //required for Functions to work

function hideSec() {
if (ng5) document.getElementById('sec1').style.visibility = "hidden"
else if (ns4) document.sec1.visibility = "hide"
else if (ie4) sec1.style.visibility ="hidden"

if (ng5) document.getElementById('sec2').style.visibility = "hidden"
else if (ns4) document.sec2.visibility = "hide"
else if (ie4) sec2.style.visibility ="hidden"
}

function showSec(n) {
hideSec();
if (ng5) document.getElementById('sec' + n).style.visibility = "visible";
else if (ns4) document.layers["sec" + n].visibility = "show";
else if (ie4) document.all["sec" + n].style.visibility = "visible";
}

function showAllSec(n) {
if (ng5) document.getElementById('sec' + n).style.visibility = "visible";
else if (ns4) document.layers["sec" + n].visibility = "show";
else if (ie4) document.all["sec" + n].style.visibility = "visible";
}



<!--
var images = [ // list images
["images/contactI.jpg","images/contactH.jpg","images/contactA.jpg"], // link 1
["images/tradingI.jpg","images/tradingH.jpg","images/tradingA.jpg"] // no comma at the end of the last index // link 10
]

var preloadImages=new Array() // preloads images
for(var i=0;i<images.length;i++) {
preloadImages[i]=new Array()
for(var j=0;j<images[i].length;j++){
preloadImages[i][j]=new Image()
preloadImages[i][j].src=images[i]
}
}

lastN = ""
lastPic=""

function mOver(obj,num){
if(lastN != obj.name){
document.images[obj.name].src = images[num][1]
}
}

function mOut(obj,num){
if(lastN != obj.name){
document.images[obj.name].src = images[num][0]
}
}

function mActive(obj,num){
document.images[obj.name].src = images[num][2]
if (lastN != "" && lastN != obj.name){
document.images[lastN].src = lastPic
}
lastN = obj.name
lastPic=images[num][0]
}

function startLink(el){
num=el.replace(/[^0-9]/g,"")
document.images[el].src = images[num][2]
lastN=el
lastPic=images[num][0]
}