how can i create menu in JavaScript for client side ??

sir i have little bit code but it is not working can any one help me
where i can navigate some pages from menu

<script language="javascript">
var mynavbar1 = new NavBar(0);

var dhtmlmenu; dhtmlmenu = new NavBarMenu(120,120);

dhtmlmenu.addItem(new NavBarMenuItem("first page","first.aspx"));

mynavbar1.addMenu(dhtmlmenu);

mynavbar1.setAlign("left");

function init()

{

var fullwidth=75;

mynavbar1.resize(fullwidth);

mynavbar1.create();

mynavbar1.moveTo(0,0);

} </script>