if (document.images) 
{
<!-- Menu images -->
var homeOn = new Image() 
homeOn.src = "images/homeOn.png";
var homeOff = new Image() 
homeOff.src = "images/homeOff.png";

var luxor_historyOn = new Image() 
luxor_historyOn.src = "images/luxor_historyOn.png";
var luxor_historyOff = new Image() 
luxor_historyOff.src = "images/luxor_historyOff.png";

var our_communityOn = new Image() 
our_communityOn.src = "images/our_communityOn.png";
var our_communityOff = new Image() 
our_communityOff.src = "images/our_communityOff.png";

var sf_historyOn = new Image() 
sf_historyOn.src = "images/sf_historyOn.png";
var sf_historyOff = new Image() 
sf_historyOff.src = "images/sf_historyOff.png";

var driversOn = new Image() 
driversOn.src = "images/driversOn.png";
var driversOff = new Image() 
driversOff.src = "images/driversOff.png";

var faresOn = new Image() 
faresOn.src = "images/faresOn.png";
var faresOff = new Image() 
faresOff.src = "images/faresOff.png";

var accountsOn = new Image() 
accountsOn.src = "images/accountsOn.png";
var accountsOff = new Image() 
accountsOff.src = "images/accountsOff.png";

var storeOn = new Image() 
storeOn.src = "images/storeOn.png";
var storeOff = new Image() 
storeOff.src = "images/storeOff.png";

var contactOn = new Image() 
contactOn.src = "images/contactOn.png";
var contactOff = new Image() 
contactOff.src = "images/contactOff.png";

var top_of_pageOn = new Image() 
top_of_pageOn.src = "images/top_of_pageOn.png";
var top_of_pageOff = new Image() 
top_of_pageOff.src = "images/top_of_pageOff.png";

var driver_roomOn = new Image() 
driver_roomOn.src = "images/driver_roomOn.png";
var driver_roomOff = new Image() 
driver_roomOff.src = "images/driver_roomOff.png";
}

function mouseOn(imgName){
if (document.images)
document[imgName].src = eval(imgName + "On.src");
}
function mouseOff(imgName){
if (document.images)
document[imgName].src = eval(imgName + "Off.src");
}
<!-- End Menu images -->