<!-- Rollover Script -->
       if (document.images) {            // Active Images
        img1on = new Image();
        img1on.src = "nav/home_up.gif";

        img1off = new Image();
        img1off.src = "nav/home.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");
        }
}
<!-- End Rollover Script -->