if (document.images) {
  image1on = new Image();
  image1on.src = "/.include/button/e/group_ir_on.png";
  image2on = new Image();
  image2on.src = "/.include/button/e/group_radio_on.png";
  image3on = new Image();
  image3on.src = "/.include/button/e/group_solar_on.png";
  image4on = new Image();
  image4on.src = "/.include/button/e/group_isas_on.png";
  image5on = new Image();
  image5on.src = "/.include/button/e/japanese_on.png";
  image6on = new Image();
  image6on.src = "/.include/button/e/news_on.png";
  imageSUZAKUon = new Image();
  imageSUZAKUon.src = "/.include/button/e/suzaku_on.png";
  image7on = new Image();
  image7on.src = "/.include/button/e/asca_on.png";
  image8on = new Image();
  image8on.src = "/.include/button/e/ginga_on.png";
  image10on = new Image();
  image10on.src = "/.include/button/e/future_on.png";
  image11on = new Image();
  image11on.src = "/.include/button/e/software_on.png";
  image12on = new Image();
  image12on.src = "/.include/button/e/conf_on.png";
  image13on = new Image();
  image13on.src = "/.include/button/e/aboutus_on.png";
  image14on = new Image();
  image14on.src = "/.include/button/e/sitemap_on.png";

  image1off = new Image();
  image1off.src = "/.include/button/e/group_ir_off.png";
  image2off = new Image();
  image2off.src = "/.include/button/e/group_radio_off.png";
  image3off = new Image();
  image3off.src = "/.include/button/e/group_solar_off.png";
  image4off = new Image();
  image4off.src = "/.include/button/e/group_isas_off.png";
  image5off = new Image();
  image5off.src = "/.include/button/e/japanese_off.png";
  image6off = new Image();
  image6off.src = "/.include/button/e/news_off.png";
  imageSUZAKUoff = new Image();
  imageSUZAKUoff.src = "/.include/button/e/suzaku_off.png";
  image10off = new Image();
  image7off = new Image();
  image7off.src = "/.include/button/e/asca_off.png";
  image8off = new Image();
  image8off.src = "/.include/button/e/ginga_off.png";
  image10off = new Image();
  image10off.src = "/.include/button/e/future_off.png";
  image11off = new Image();
  image11off.src = "/.include/button/e/software_off.png";
  image12off = new Image();
  image12off.src = "/.include/button/e/conf_off.png";
  image13off = new Image();
  image13off.src = "/.include/button/e/aboutus_off.png";
  image14off = new Image();
  image14off.src = "/.include/button/e/sitemap_off.png";
}

function turnOn(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "on.src");
  }
}
x2
function turnOff(imageName) {
  if (document.images) {
    document[imageName].src = eval(imageName + "off.src");
  }
}