function initPage()
{
     var nav = document.getElementById("nav");
     if (nav)
     {
          var nodes = nav.getElementsByTagName("li");
          for (var i = 0; i < nodes.length; i++)
          {
               nodes[i].onmouseover = function () 
               {
                    if (this.className.indexOf("hover") == -1)
                    {
                         this.className += " hover";
                    }
               }
               nodes[i].onmouseout = function ()
               {
                    this.className = this.className.replace(" hover", "");
               }
          }
     }
}

if (window.attachEvent && !window.opera)
     window.attachEvent("onload", initPage);