function observeMenu() {
    var menus=document.getElementById("navigation").getElementsByTagName("a")
    for (var t=0; t<menus.length; t++){
        menus[t].onmouseover=function(){
            this.parentNode.className.match(new RegExp('(\\s|^)active(\\s|$)')) ? this.parentNode.className = "active on" : this.parentNode.className = "on"
        }
        menus[t].onmouseout=function(){
            this.parentNode.className.match(new RegExp('(\\s|^)active(\\s|$)')) ? this.parentNode.className = "active" : this.parentNode.className = ""
        }
    }
}

if (window.addEventListener)
window.addEventListener("load", observeMenu, false)
else if (window.attachEvent)
window.attachEvent("onload", observeMenu)