function toggleHidden(linkObj, containerId) {

    var imgId = containerId + 'Img';
    var imgObj = $(imgId);
    var imgSrc = imgObj.src;
    var containerObj = $(containerId);
    var isHidden = imgSrc.indexOf('plus.gif', 0) >= 0;

    if (isHidden) {
        containerObj.removeClassName("Hidden");
        containerObj.addClassName("Visible");
        imgObj.src = imgSrc.replace("plus", "minus");
    } else {
        containerObj.removeClassName("Visible");
        containerObj.addClassName("Hidden");
        imgObj.src = imgSrc.replace("minus", "plus");
    }
}