if (document.images) {
  image2 = new Image();
  image2.src = "img/new_is.gif";
  image3 = new Image();
  image3.src = "img/new_chapters.gif";
  image4 = new Image();
  image4.src = "img/new_start.gif";
  
  imageoff = new Image();
  imageoff.src = "img/blank.gif";
}
function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}