var iOffender = 1;

function switchImg (oLink, iImgId)
{
    var oImg = oLink.getElementsByTagName("img")[0];
    // get the main image
    var oMainImage = document.getElementById("mainImage");
    if (oMainImage == null)
        return true;
    
    // get the ID of the image we clicked on
    oMainImage.setAttribute("src", aoImg[iImgId-1]['activ'].getAttribute("src"));
    if (iOffender != null)
    {
        var foo = iOffender;    // mmmmrrr...
        oLink.onclick = function() { return switchImg(oLink, foo); }
        oImg.setAttribute ("src", aoImg[iOffender-1]['inactiv'].getAttribute("src"));
    }
    iOffender = iImgId;
    
    return false;
}