if (document.images) {            // Active Images

            backon = new Image();
            backon.src = "/_nav/back_1.gif";
            dataon = new Image();
            dataon.src = "/_nav/data_1.gif";
            nexton = new Image();
            nexton.src = "/_nav/next_1.gif";
            stopon = new Image();
            stopon.src = "/_nav/stop_1.gif";

            backoff = new Image();
            backoff.src = "/_nav/back_0.gif";
            dataoff = new Image();
            dataoff.src = "/_nav/data_0.gif";
            nextoff = new Image();
            nextoff.src = "/_nav/next_0.gif";
            stopoff = new Image();
            stopoff.src = "/_nav/stop_0.gif";

        }

// Function to 'activate' images.
function imgOn(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "on.src");
        }
}

// Function to 'deactivate' images.
function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}