function addLoadEvent(func) 
{

    var oldonload = window.onload;
    
    if (typeof window.onload != 'function')
    {
    
        window.onload = func;
        
    }else{
    
        window.onload = function()
        
        {
            if (oldonload)
            {
            
                oldonload();
                
            }
            
            func();
            
        }
    }
}

var imgNames = [ "home", "press", "event", "awards", "sponsors", "winners", "buy", "contact", "past", "shortlist", "enter" ];
   
function navMenu()
{

    for (var x = 1; x < 12; x++)
    {

        if (document.getElementById("nav" + x))
        {
            var img = document.getElementById("nav" + x);
            img.index = x; // expando property
        
            img.onmouseover = function()
            {
            
                this.src = "./img/nav/" + imgNames[ this.index - 1 ] + "_on.gif";
                
            }
            
            img.onmouseout = function()
            {
            
                this.src = "./img/nav/" + imgNames[ this.index - 1 ] + ".gif";
                
            }
           
        }
    
    }

}

addLoadEvent(navMenu);