function newImage(arg) {
    if (document.images) {
        rslt = new Image();
        rslt.src = arg;
        return rslt;
    }
}

function changeImages() {
    if (document.images && (preloadFlag == true)) {
        for (var i=0; i<changeImages.arguments.length; i+=2) {
            document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
        }
    }
}

var preloadFlag = false;
function preloadImages() {
    if (document.images) {
        function_over = newImage("/images/kpad/function-over.jpg");
        stay_over = newImage("/images/kpad/stay-over.jpg");
        away_over = newImage("/images/kpad/away-over.jpg");
        chime_over = newImage("/images/kpad/chime-over.jpg");
        reset_over = newImage("/images/kpad/reset-over.jpg");
        medical_over = newImage("/images/kpad/medical-over.jpg");
        exit_over = newImage("/images/kpad/exit-over.jpg");
        police_over = newImage("/images/kpad/police-over.jpg");
        preloadFlag = true;
    }
}