function func_hover(){
this.className = this.className + '-hover';
}

function func_out(){
this.className = this.className.replace('-hover','');
}

function inihover(){
        var lis = document.getElementsByName('rollOver');
        for (i=0; i<lis.length; i++){
                lis[i].onmouseover = func_hover;
                lis[i].onmouseout = func_out;
                }
}

window.onload = inihover;