function setFavorite(fID) {
  feedID = fID
  var check_val = document.getElementById("f_" + fID).src.split("_");
  if (check_val[1] == "off.png") {
    document.getElementById("f_" + fID).src = "/images/icons/favorite_waiting.png";
    callServer("/favorites.php?ID=" + fID, favResponse);
  } else {
    document.getElementById("f_" + fID).src = "/images/icons/favorite_waiting.png";
    callServer("/favorites.php?DELETE=" + fID, favResponse);
  }
}

function favResponse () {
  if (xmlHttp.readyState == "4") {
    if (xmlHttp.responseText == "must login") {
      alert("You must login in order to set this feed as a favorite.");
      document.getElementById("f_" + feedID).src = "/images/icons/star_off.png";
      return 0;
    }
    if (xmlHttp.responseText == "added") {
      document.getElementById("f_" + feedID).src = "/images/icons/star_on.png";
      return 1;
    }
    if (xmlHttp.responseText == "deleted") {
      document.getElementById("f_" + feedID).src = "/images/icons/star_off.png";
      return 1;
    }
    if (xmlHttp.responseText == "error") {
      alert("There was an error processing your request. Item was not saved.");
      return 1;
    }
  }
}