menuHover = function (nav) {
    var sfEls = document.getElementById(nav).getElementsByTagName("li");
    for (var i = 0; i < sfEls.length; i++) {
        sfEls[i].onmouseover = function () {
            this.className += " sfhover";
        }
        sfEls[i].onmouseout = function () {
            this.className = this.className.replace(new RegExp("\\s?sfhover\\b"), "");
        }
    }

    var listItem = document.getElementById(nav).getElementsByTagName('ul');
    for (var i = 0; i < listItem.length; i++) {
        listItem[i].onmouseover = function () {
            var changeStyle = this.parentNode.getElementsByTagName('a');
            changeStyle[0].className = "tab-on";
        }

        listItem[i].onmouseout = function () {
            var changeStyle = this.parentNode.getElementsByTagName('a');
            changeStyle[0].className = "tab";
        }
    }
}

function addEvent(obj, type, fn) {
    if (obj.attachEvent) {
        obj['e' + type + fn] = fn;
        obj[type + fn] = function () { obj['e' + type + fn](window.event); }
        obj.attachEvent('on' + type, obj[type + fn]);
    } else
        obj.addEventListener(type, fn, false);
}
function removeEvent(obj, type, fn) {
    if (obj.detachEvent) {
        obj.detachEvent('on' + type, obj[type + fn]);
        obj[type + fn] = null;
    } else
        obj.removeEventListener(type, fn, false);
}

addEvent(window, 'load', function () { menuHover('nav-list'); });