if (document.images) {

  image1on = new Image();
  image1on.src = "pics/nav_keynotes_on.gif";
  image2on = new Image();
  image2on.src = "pics/nav_who_on.gif";  
  image3on = new Image();
  image3on.src = "pics/nav_talking_on.gif";  
  image4on = new Image();
  image4on.src = "pics/nav_hire_on.gif";
  image5on = new Image();
  image5on.src = "pics/nav_campus_on.gif";
  image6on = new Image();
  image6on.src = "pics/nav_fun_on.gif";
  image7on = new Image();
  image7on.src = "pics/nav_store_on.gif";
  image8on = new Image();
  image8on.src = "pics/nav_contact_on.gif";
  image9on = new Image();
  image9on.src = "pics/nav_stand_on.gif";
  image10on = new Image();
  image10on.src = "pics/nav_home_on.gif";
  
  
  image1off = new Image();
  image1off.src = "pics/nav_keynotes_off.gif";
  image2off = new Image();
  image2off.src = "pics/nav_who_off.gif";
  image3off = new Image();
  image3off.src = "pics/nav_talking_off.gif";
  image4off = new Image();
  image4off.src = "pics/nav_hire_off.gif";
  image5off = new Image();
  image5off.src = "pics/nav_campus_off.gif";
  image6off = new Image();
  image6off.src = "pics/nav_fun_off.gif";  
  image7off = new Image();
  image7off.src = "pics/nav_store_off.gif";
  image8off = new Image();
  image8off.src = "pics/nav_contact_off.gif";
  image9off = new Image();
  image9off.src = "pics/nav_stand_off.gif";
  image10off = new Image();
  image10off.src = "pics/nav_home_off.gif";
    
}

function turnOn(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "on.src")
  }
}

function turnOff(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "off.src")
  }
}