// JavaScript Document

function button_on ( imgId )
{
  if ( document.images )
  {
    butOn = "images/" + imgId + "-over.jpg"; 
    document.getElementById(imgId).src = butOn;
  }
}

function button_off ( imgId )
{
  if ( document.images )
  {
    butOff = "images/" + imgId + ".jpg"; 
    document.getElementById(imgId).src = butOff;
  }
}

function doPreloadImages()
{  
  preload1 = new Image();
  preload1.src = "images/NAVIGATION_01-over.jpg";

  preload2 = new Image();
  preload2.src = "images/NAVIGATION_03-over.jpg";

  preload3 = new Image();
  preload3.src = "images/NAVIGATION_05-over.jpg";
  
  preload4 = new Image();
  preload4.src = "images/NAVIGATION_07-over.jpg";
  
  preload5 = new Image();
  preload5.src = "images/NAVIGATION_09-over.jpg";
  
  preload6 = new Image();
  preload6.src = "images/NAVIGATION_11-over.jpg";  
}