if (/MSIE [56]/.test(navigator.userAgent) && !/Opera/.test(navigator.userAgent))
    (function () {
        var _previousOnload = window.onload;

        function _enhance(o)
        {
            if (o)
            {
                if (o.tagName == 'LI')
                {
                    o._className1 = o.className;
                    o._className2 = (o.className ? o.className + ' ' : '') + 'hover';

                    o.onmouseover = function () { this.className = this._className2; }
                    o.onmouseout = function () { this.className = this._className1; }
                }

                for (var i = 0; i < o.childNodes.length; i++)
                    _enhance(o.childNodes[i]);

                if (o.tagName == 'UL' && !/MSIE 5.0/.test(navigator.userAgent))
                {
                    var f = document.createElement('IFRAME');
                    f.src = 'about:blank';
                    f.style.position = 'absolute';
                    f.style.zIndex = -100;
                    f.style.setExpression('left', '-this.parentNode.clientLeft + "px"');
                    f.style.setExpression('top', '-this.parentNode.clientTop + "px"');
                    f.style.setExpression('width', 'this.parentNode.offsetWidth + "px"');
                    f.style.setExpression('height', 'this.parentNode.offsetHeight + "px"');
                    f.style.filter = 'Alpha(opacity=0)';
                    o.insertBefore(f, o.firstChild);
                }
            }
        }

        window.onload = function ()
        {
            _enhance(document.getElementById('mainNav'));

            return !_previousOnload || _previousOnload();
        }
    })();