function roll_over2(img_name, img_src) {
    var image = document.getElementById(img_name);
    if (image != null)
        image.src = img_src;
}

function showHide(show, hide) {
    document.getElementById(show).style.display = "block";
    document.getElementById(hide).style.display = "none";
}
        
function hide(id) {
    document.getElementById(id).style.display = "none";
}        
        
function roll_over(image, id) {
    document.images[id].src = image;
}