function window_onload()
{
    // set image rollovers

    var imgs = document.getElementsByTagName("IMG");

    for (var i = 0; i < imgs.length; i++)
    {
        var img = imgs[i];
        
        if (img.src.indexOf('-off') >= 0)
        {
            img.onmouseover = RolloverImage;
            img.onmouseout = RolloffImage;
        }
    }
}

function RolloverImage()
{
    var img = event.srcElement;

    if (img.src)
        img.src = img.src.replace(/-off/, '-roll');
}

function RolloffImage()
{
    var img = event.srcElement;

    if (img.src)
        img.src = img.src.replace(/-roll/, '-off');
}