if(document.images) {

  image01 = new Image;
  image02 = new Image;
  image11 = new Image;
  image12 = new Image;
  image21 = new Image;
  image22 = new Image;
  image31 = new Image;
  image32 = new Image;
  image41 = new Image;
  image42 = new Image;

// source images

  image01.src = "images/bt_About-off.gif";
  image02.src = "images/bt_About-on.gif";
  image11.src = "images/bt_Contact-off.gif";
  image12.src = "images/bt_Contact-on.gif";
  image21.src = "images/bt_Home-off.gif";
  image22.src = "images/bt_Home-on.gif";
  image31.src = "images/bt_Processing-off.gif";
  image32.src = "images/bt_Processing-on.gif";
  image41.src = "images/bt_Products-off.gif";
  image42.src = "images/bt_Products-on.gif";

}

/// MouseOver Function

function swapOn(imgLocation) {
  if(document.images) {
    document.images[imgLocation].src = eval(imgLocation + "2.src");
  }
}

// MouseOut Function

function swapOff(imgLocation) {
  if(document.images) {
    document.images[imgLocation].src = eval(imgLocation + "1.src");
  }
}

// end hiding script -->