doors = new Array(
  'supreme-door', 'mlk-door', 'gerrymander-door'
);

function init() {
  hilite();
  for (var i = 0; i < doors.length; i++) {
    var door = $(doors[i]);
    door.onmouseover = rollover;
    door.onmouseout = rollout;
  }
  $('screenshot').onmouseover = unhilite;
  $('screenshot').onmouseout = hilite;
}

function shift(id, x, y) {
  $(id).style.backgroundPosition = "" + x + "px " + y + "px"; 
}

function rollover() {
  var offset = (doors.indexOf(this.id) + 1) * -274;
  shift('screenshot', offset, 0);
}

function rollout() {
  var offset = (doors.indexOf(this.id) + 1) * -274;
  shift('screenshot', 0, 0);
}

function hilite() {
  for (var i = 0; i < doors.length; i++) {
    var door = $(doors[i]);
    door.style.border = "2px solid yellow";
  }
}

function unhilite() {
  for (var i = 0; i < doors.length; i++) {
    var door = $(doors[i]);
    door.style.border = "none";
  }
}

function signguestbook() {
  var url = "guestbook.php";
  var target = "email-txt-form";
  if (!$F('guestbook_email')) {
    return false;
  } else {
    var params = "guestbook_email=" + $F('guestbook_email');
  }
  var ajax = new Ajax.Updater(
    target,
    url,
    {
      method: "post",
      parameters: params,
      asynchronous: true
    });
  new Effect.Highlight(target, {startcolor: '#ad3d3d', endcolor: '#ffffff'});
  return false;
}

window.onload = init;