var on_image_array = null;
var off_image_array = null;
var status_text_array = null;

if (document.images)
{
  on_image_array = new Array();
  off_image_array = new Array();
  status_text_array = new Array();
}

function turn_on(image_name)
{
  if (document.images)
  {
    document[image_name].src = on_image_array[image_name].src;
    window.status = status_text_array[image_name];
  }
  
  return true;
}

function turn_off(image_name)
{
  if (document.images)
  {
    document[image_name].src = off_image_array[image_name].src;
    window.status = "";
  }

  return true;
}

function preload_image(image_name, status_text)
{
  with (document)
  {
    off_image_array[image_name] = new Image();
    off_image_array[image_name].src = "images/" + image_name + "_off.gif";

    on_image_array[image_name] = new Image();
    on_image_array[image_name].src = "images/" + image_name + "_over.gif";

    status_text_array[image_name] = status_text;
  }
}