function setOpacity(obj, opacity) {
    opacity = (opacity == 100) ? 99.999 : opacity;

    // IE/Win
    obj.style.filter = "alpha(opacity:" + opacity + ")";

    // Safari<1.2, Konqueror
    obj.style.KHTMLOpacity = opacity / 100;

    // Older Mozilla and Firefox
    obj.style.MozOpacity = opacity / 100;

    // Safari 1.2, newer Firefox and Mozilla, CSS3
    obj.style.opacity = opacity / 100;
};
function fadeIn(objId, opacity) {
    if (document.getElementById) {
        obj = document.getElementById(objId);
        if (opacity <= 100) {
            setOpacity(obj, opacity);
            opacity += 50;
            window.setTimeout("fadeIn('" + objId + "'," + opacity + ")", 100);
        }
        else { setOpacity(obj, 100); }
    }
};

function initImage(img_name) {
    imageId = img_name;
    image = document.getElementById(imageId);
    setOpacity(image, 0);
    image.style.visibility = 'visible';
    fadeIn(imageId, 0);
};
function roll_over(img_name, img_src) {
    document[img_name].src = img_src;
    initImage(img_name);
};