Ext.onReady(function() {

    if (Ext.isIE) {
        addMouseHoverClass("nav", "sfhover");
    }

});

function addMouseHoverClass(elementId, className) {
    var elements = document.getElementById(elementId).getElementsByTagName("LI");
    for (var i = 0; i < elements.length; i++) {
        elements[i].onmouseover = function() {
            this.className += " " + className;
        }
        elements[i].onmouseout = function() {
            this.className = this.className.replace(new RegExp(" " + className + "\\b"), "");
        }
    }
}