if (document.images) {

  img_nav_sub1_1on = new Image();
  img_nav_sub1_1on.src = "../_img/nav_sub1_1over.gif";
  img_nav_sub1_2on = new Image();
  img_nav_sub1_2on.src = "../_img/nav_sub1_2over.gif"; 
  img_nav_sub1_3on = new Image();
  img_nav_sub1_3on.src = "../_img/nav_sub1_3over.gif";
  img_nav_sub1_4on = new Image();
  img_nav_sub1_4on.src = "../_img/nav_sub1_4over.gif";
  img_nav_sub1_5on = new Image();
  img_nav_sub1_5on.src = "../_img/nav_sub1_5over.gif";
  img_nav_sub1_6on = new Image();
  img_nav_sub1_6on.src = "../_img/nav_sub1_6over.gif";
  img_nav_sub1_7on = new Image();
  img_nav_sub1_7on.src = "../_img/nav_sub1_7over.gif";
  img_nav_sub1_8on = new Image();
  img_nav_sub1_8on.src = "../_img/nav_sub1_8over.gif";
  img_nav_sub1_9on = new Image();
  img_nav_sub1_9on.src = "../_img/nav_sub1_9over.gif";

  img_nav_sub1_1off = new Image();
  img_nav_sub1_1off.src = "../_img/nav_sub1_1off.gif";
  img_nav_sub1_2off = new Image();
  img_nav_sub1_2off.src = "../_img/nav_sub1_2off.gif";
  img_nav_sub1_3off = new Image();
  img_nav_sub1_3off.src = "../_img/nav_sub1_3off.gif";
  img_nav_sub1_4off = new Image();
  img_nav_sub1_4off.src = "../_img/nav_sub1_4off.gif";
  img_nav_sub1_5off = new Image();
  img_nav_sub1_5off.src = "../_img/nav_sub1_5off.gif";
  img_nav_sub1_6off = new Image();
  img_nav_sub1_6off.src = "../_img/nav_sub1_6off.gif";
  img_nav_sub1_7off = new Image();
  img_nav_sub1_7off.src = "../_img/nav_sub1_7off.gif";
  img_nav_sub1_8off = new Image();
  img_nav_sub1_8off.src = "../_img/nav_sub1_8off.gif";
  img_nav_sub1_9off = new Image();
  img_nav_sub1_9off.src = "../_img/nav_sub1_9off.gif";

}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}