function showPreview(id) {
  if (document.selection) {
    document.getElementById('link' + id).innerText = "Close preview";
  }
  else {
    document.getElementById('link' + id).replaceChild(document.createTextNode("Close preview"), document.getElementById('link' + id).childNodes[0]);
  }
  document.getElementById('link' + id).href = "javascript:hidePreview('" + id + "')";
  document.getElementById(id).style.display = "block";
}

function hidePreview(id) {
  if (document.selection) {
    document.getElementById('link' + id).innerText = "Show preview";
  }
  else {
    document.getElementById('link' + id).replaceChild(document.createTextNode("Show preview"), document.getElementById('link' + id).childNodes[0]);
  }
  document.getElementById('link' + id).href = "javascript:showPreview('" + id + "')";
  document.getElementById(id).style.display = "none";
}