var startList = function() {
    if (document.all && document.getElementById) {
        var navRoot = document.getElementById("drop");
        for (i=0; i<navRoot.childNodes.length; i++) {
            var node = navRoot.childNodes[i];
            if (node.nodeName == "LI") {
                
                node.onmouseover = function() {
                                       this.className+=" over";
                                   };
                
                node.onmouseout = function() {
                                      this.className=this.className.replace(" over", "");
                                  };
            }
        }
     }
};

window.onload = startList;