var defaultImage = 'nil';

if (document.images)
{
    var menuon = false; // the menu is not active yet


    var nav1a=new Image();
    nav1a.src="/images/bu_shop_over.gif";
    var nav1=new Image();
    nav1.src="/images/bu_shop.gif";
    
    var nav2a=new Image();
    nav2a.src="/images/bu_comp_over.gif";
    var nav2=new Image();
    nav2.src="/images/bu_comp.gif";
    
    var nav3a=new Image();
    nav3a.src="/images/bu_voucher_over.gif";
    var nav3=new Image();
    nav3.src="/images/bu_voucher.gif";
    var nav4a=new Image();
    nav4a.src="/images/bu_askRog_over.gif";
    var nav4=new Image();
    nav4.src="/images/bu_askRog.gif"; 
}

function stickymenuOn(imgName)
{
    menuon = true; // the menu is now active
    if (defaultImage == 'nil')
    {
        roll(imgName);
    }
    else
    {
        roll(imgName);
        if (imgName != defaultImage)
        {
            unroll(defaultImage);
        }
    }
}

function stickymenuOff(imgName)
{
    menuon = false; // the menu is no longer active
    if (defaultImage == 'nil')
    {
        unroll(imgName);
    }
    else
    {
        if (imgName != defaultImage)
        {
            unroll(imgName);
            timerID = setTimeout('if (!menuon) roll("'+defaultImage+'")', 1);
        }
    }
}

function roll(imgName)
{
    if ('nil' != imgName)
        document[imgName].src = eval(imgName + "a.src");
}
function unroll(imgName)
{
    if ('nil' != imgName)
        document[imgName].src = eval(imgName + ".src");
}