// JavaScript Document
function combo1() {
  document.all.contents1.style.visibility="visible";
  document.all.contents2.style.visibility="hidden";
  document.all.contents3.style.visibility="hidden";
}

function combo2() {
  document.all.contents1.style.visibility="hidden";
  document.all.contents2.style.visibility="visible";
  document.all.contents3.style.visibility="hidden";
}

function combo3() {
  document.all.contents1.style.visibility="hidden";
  document.all.contents2.style.visibility="hidden";
  document.all.contents3.style.visibility="visible";
}

function combo4() {
  document.all.contents1.style.visibility="hidden";
  document.all.contents2.style.visibility="hidden";
  document.all.contents3.style.visibility="hidden";
}