/**
 * Add hover-effect for all list items, necessary for all IE lesser than 7
 */
addHover = function() {
    // Get all list items
    var liItems = $$("ul#navi li");
    // Pass through all list items
    for (var i=0; i < liItems.length; i++) {
        // Add mouseover-function
        liItems[i].onmouseover = function() {
            this.className += " hover";
        }
        // Add mouseout-function
        liItems[i].onmouseout =function () {
            this.className = this.className.replace(" hover", "");
        }
    }
}
addOnload(addHover);