if(document.images) {
  sb1_on = new Image();
  sb1_on.src = "/images/sb1_.gif";
  sb1_off = new Image();
  sb1_off.src ="/images/sb1.gif";

  sb2_on = new Image();
  sb2_on.src = "/images/sb2_.gif";
  sb2_off = new Image();
  sb2_off.src ="/images/sb2.gif";

  sb3_on = new Image();
  sb3_on.src = "/images/sb3_.gif";
  sb3_off = new Image();
  sb3_off.src ="/images/sb3.gif";

  sb4_on = new Image();
  sb4_on.src = "/images/sb4_.gif";
  sb4_off = new Image();
  sb4_off.src ="/images/sb4.gif";

  sb5_on = new Image();
  sb5_on.src = "/images/sb5_.gif";
  sb5_off = new Image();
  sb5_off.src ="/images/sb5.gif";

  sb6_on = new Image();
  sb6_on.src = "/images/sb6_.gif";
  sb6_off = new Image();
  sb6_off.src ="/images/sb6.gif";

  sb7_on = new Image();
  sb7_on.src = "/images/sb7_.gif";
  sb7_off = new Image();
  sb7_off.src ="/images/sb7.gif";
 }

function img_on(iName) {
 if(document.images) {
  imgOn = eval(iName + "_on.src");
  document [iName].src = imgOn;
  return true;
 }
}

function img_off(iName) {
 if(document.images) {
  imgOff = eval(iName + "_off.src");
  document [iName].src = imgOff;
  return true;
 }
}