function initBanner(){
  var bannercontainer = document.getElementById("bannercontainer");
  bannercontainer.style.position = "absolute";
  bannercontainer.style.display = "block";
  bannercontainer.style.overflow = "hidden";
  bannercontainer.style.height = "100px";
  bannercontainer.style.left = "32%";
}

function showBanner(){
  document.getElementById("bannercontainer").style.height = "320px";
}

function hideBanner(){
  document.getElementById("bannercontainer").style.height = "100px";
}