var VALID_IMAGE_FILES = ".jpg, .gif, .png, .jpeg, .bmp";

function AdTypeChange()
{
  adtype = document.getElementById("ad_type").value;
  if (adtype == "img_link")
  {
    o = document.getElementById("img_link_block");
    o.style.display = "block";

    o = document.getElementById("img_url_block");
    o.style.display = "block";

    o = document.getElementById("img_browse_block");
    o.style.display="none";

    o = document.getElementById("iframe_script_block");
    o.style.display = "none";
  }
  else if (adtype == "iframe_or_script")
  {
    o = document.getElementById("iframe_script_block");
    o.style.display = "block";

    o = document.getElementById("img_browse_block");
    o.style.display = "none";

    o = document.getElementById("img_link_block");
    o.style.display = "none";

    o = document.getElementById("img_url_block");
    o.style.display = "none";
  }
  else
  {
    o = document.getElementById("img_browse_block");
    o.style.display="block";

    o = document.getElementById("img_link_block");
    o.style.display = "none";

    o = document.getElementById("img_url_block");
    o.style.display = "block";

    o = document.getElementById("iframe_script_block");
    o.style.display = "none";
  }
}

function AddExitAd()
{
  adtype = document.getElementById("ad_type").value;
  if (adtype == "img_link")
  {
    s = document.getElementById("ad_exit_img_url").value;
    s = trim_s(s);
    if (s == "")
    {
      alert("Image URL is required");
      return false;
    }
    else
    {
      sLen = s.length;
      sExt = s.substring(sLen-4);
      sExt = sExt.toLowerCase();
      // SEE IF extension is in VALID_IMAGE_FILES
      if (VALID_IMAGE_FILES.indexOf(sExt) == -1)
      {
        alert("URL does not point to an image file");
        return false;
      }
    }
    s = document.getElementById("img_url").value;
    s = trim_s(s);
    if (s == "")
    {
      alert("Ad URL is required");
      return false;
    }
  }
  else if (adtype == "iframe_or_script")
  {
    s = document.getElementById("iframe_script_code").value;
    s = trim_s(s);
    if (s == "")
    {
      alert("Ad code is required");
      return false;
    }
  }
  else
  {
    s = document.getElementById("ad_exit_img_file").value;
    s = trim_s(s);
    if (s == "")
    {
      alert("Please browse ad image to upload");
      return false;
    }
    s = document.getElementById("img_url").value;
    s = trim_s(s);
    if (s == "")
    {
      alert("Ad URL is required");
      return false;
    }
  }
  return true;
}

function trim_s(s)
{
  s = s.replace(/^\s+|\s+$/g, '') ;
  return s;
}