nav1up = new Image();
  nav1up.src = "images/nav_1_up.gif";
  nav1dn = new Image();
  nav1dn.src = "images/nav_1_dn.gif";
  nav2up = new Image();
  nav2up.src = "images/nav_2_up.gif";
  nav2dn = new Image();
  nav2dn.src = "images/nav_2_dn.gif";
  nav3up = new Image();
  nav3up.src = "images/nav_3_up.gif";
  nav3dn = new Image();
  nav3dn.src = "images/nav_3_dn.gif";
  nav4up = new Image();
  nav4up.src = "images/nav_4_up.gif";
  nav4dn = new Image();
  nav4dn.src = "images/nav_4_dn.gif";
  nav5up = new Image();
  nav5up.src = "images/nav_5_up.gif";
  nav5dn = new Image();
  nav5dn.src = "images/nav_5_dn.gif";
  nav6up = new Image();
  nav6up.src = "images/nav_6_up.gif";
  nav6dn = new Image();
  nav6dn.src = "images/nav_6_dn.gif";

function navSwap() { 
  document[navSwap.arguments[0]].src = eval(navSwap.arguments[1] + ".src");
}