if (document.images) {

        nav1on = new Image();
        nav1on.src = "images/nav-home-on.gif"; 
        nav1off = new Image();
        nav1off.src = "images/nav-home-off.gif";
        nav2on = new Image();
        nav2on.src = "images/nav-history-on.gif"; 
        nav2off = new Image();
        nav2off.src = "images/nav-history-off.gif";
        nav3on = new Image();
        nav3on.src = "images/nav-credits-on.gif"; 
        nav3off = new Image();
        nav3off.src = "images/nav-credits-off.gif";
        nav4on = new Image();
        nav4on.src = "images/nav-facility-on.gif"; 
        nav4off = new Image();
        nav4off.src = "images/nav-facility-off.gif";
        nav5on = new Image();
        nav5on.src = "images/nav-location-on.gif"; 
        nav5off = new Image();
        nav5off.src = "images/nav-location-off.gif";
        nav6on = new Image();
        nav6on.src = "images/nav-contact-on.gif"; 
        nav6off = new Image();
        nav6off.src = "images/nav-contact-off.gif";

}
function changeImages(){
        if(document.images){
                for (var i=0; i<changeImages.arguments.length; i+=2) {
                        document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
                }
        }
}




var ns6=document.getElementById&&!document.all
var ie=document.all

function changeto(e,highlightcolor){
source=ie? event.srcElement : e.target
if (source.tagName=="TR"||source.tagName=="TABLE")
return
while(source.tagName!="TD"&&source.tagName!="HTML")
source=ns6? source.parentNode : source.parentElement
if (source.style.backgroundColor!=highlightcolor&&source.id!="ignore")
source.style.backgroundColor=highlightcolor
}

function contains_ns6(master, slave) { //check if slave is contained by master
while (slave.parentNode)
if ((slave = slave.parentNode) == master)
return true;
return false;
}

function changeback(e,originalcolor){
if
(ie&&(event.fromElement.contains(event.toElement)||source.contains(event.toElement)||source.id=="ignore")||source.tagName=="TR"||source.tagName=="TABLE")
return
else if (ns6&&(contains_ns6(source, e.relatedTarget)||source.id=="ignore"))
return
if (ie&&event.toElement!=source||ns6&&e.relatedTarget!=source)
source.style.backgroundColor=originalcolor
}