startList = function() 
{ 
    var nodes = document.getElementById("nav").getElementsByTagName("li");
    for ( var i=0; i<nodes.length; i++ ) 
    { 
        nodes[i].onmouseover = function() 
        {
            this.className += " over"; 
        } 
        nodes[i].onmouseout = function() 
        { 
            this.className = this.className.replace(new RegExp(" over\\b"), ""); 
        } 
    } 
}
 
if ( window.attachEvent )
    window.attachEvent( "onload", startList );