// Displays an element based on element ID
    function showImg(imgId) {
        $(imgId).style.visibility="visible";
    }

    // Hides an element based in element ID
    function hideImg (imgId) {
        $(imgId).style.visibility="hidden";
    }

    // Sets the opacity of an element, based on element reference.
    function setOpacity(elm, opacity) {
        elm.style.opacity = opacity;
        elm.style.mozOpacity = opacity;
        elm.style.filter = "alpha(opacity=" + (+opacity*100)  + ")";
    }

    function makeOpaque (elm, col) {
        setOpacity(elm, .9);
        if (elm.style.filter && window.event) {
            setOpacity($('ABB_rtop' + col), .9);
            setOpacity($('ABB_rbottom' + col), .9);
        }
    }

    function makeTransparent(elm, col) {
        setOpacity(elm, .7);
        if (elm.style.filter && window.event) {
            setOpacity($('ABB_rtop' + col), .7);
            setOpacity($('ABB_rbottom' + col), .7);
        }
    }