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) {
    nav_mkk_02_over = newImage("/images/nav/nav-mkk_02-over.jpg");
    nav_mkk_03_over = newImage("/images/nav/nav-mkk_03-over.jpg");
    nav_mkk_04_over = newImage("/images/nav/nav-mkk_04-over.jpg");
    nav_mkk_05_over = newImage("/images/nav/nav-mkk_05-over.jpg");
    nav_mkk_06_over = newImage("/images/nav/nav-mkk_06-over.jpg");
    nav_mkk_07_over = newImage("/images/nav/nav-mkk_07-over.jpg");
    nav_mkk_08_over = newImage("/images/nav/nav-mkk_08-over.jpg");
    preloadFlag = true;
  }
}