function toggleVisible(elementID, toggleImgID) {
    var elem = document.getElementById(elementID);
    var image = document.getElementById(toggleImgID);
    if(!elem || !image)
        return true;
    if(elem.style.display=="none") {
        elem.style.display="block";
        image.src="images/minus.jpg";
        }
    else {
        elem.style.display="none";
        image.src="images/plus.jpg";
        }
    return true;
    }