javascript-card-trick/index.html at main · steventine/javascript-card-trick · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>AI Mind Reader</title>
<style>
  body { font-family: system-ui, sans-serif; padding: 0.5rem; max-width: 32rem; margin: 0 auto; }
  h1 { margin: 0.2rem 0 0.35rem 0; font-size: 1.4rem; }
  p { margin: 0.35rem 0; }
  .picker { margin-bottom: 0.5rem; }
  .picker-section { margin-bottom: 0.4rem; }
  .picker-section label { display: block; font-size: 0.85rem; color: #666; margin-bottom: 0.2rem; }
  .rank-cards { display: flex; flex-direction: column; gap: 0.25rem; }
  .rank-row { display: flex; gap: 0.25rem; flex-wrap: wrap; }
  .suit-cards { display: flex; gap: 0.25rem; flex-wrap: wrap; }
  .rank-card, .suit-card { width: 2.5rem; height: 3rem; border: 1px solid #ccc; border-radius: 4px; display: flex; align-items: center; justify-content: center; font-size: 1rem; background: #fff; cursor: pointer; user-select: none; }
  .rank-card:hover, .suit-card:hover { border-color: #666; background: #f8f8f8; }
  .rank-card.selected, .suit-card.selected { border-color: #1a4d6d; border-width: 2px; background: #e8f4fc; }
  .suit-card.red { color: #c00; }
  .suit-card { font-size: 1.25rem; }
  .add-row { margin-top: 0.4rem; }
  .cards-row { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; margin: 0.4rem 0; }
  .reset-row { margin-top: 2rem; }
  .reset-row button { padding: 0.35rem 0.6rem; font-size: 0.95rem; cursor: pointer; border-radius: 4px; border: 1px solid #d0d0d0; background: #e8e8e8; color: #777; }
  .reset-row button:hover { background: #ddd; color: #555; }
  .reset-row button.revealed { border-color: #1a4d6d; background: #e8f4fc; color: #1a4d6d; }
  .reset-row button.revealed:hover { background: #d0e8f4; }
  footer { margin-top: 1rem; padding-top: 0.5rem; font-size: 0.8rem; color: #666; }
  footer a { color: #1a4d6d; }
  .pile { display: flex; gap: 0.4rem; flex-wrap: wrap; min-height: 5rem; }
  .card-slot { width: 4rem; height: 5.5rem; border: 1px solid #ccc; border-radius: 6px; display: flex; align-items: center; justify-content: center; gap: 0.25rem; font-size: 1.25rem; background: #fff; }
  .card-slot.empty { background: #f0f0f0; color: #999; font-size: 0.9rem; }
  .card-slot.red { color: #c00; }
  .card-back { width: 4rem; height: 5.5rem; border: 2px solid #1a4d6d; border-radius: 6px; background: linear-gradient(135deg, #1a4d6d 0%, #2d6a8f 100%); cursor: pointer; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 0.25rem; padding: 0.25rem; box-sizing: border-box; }
  .card-back:hover { opacity: 0.95; transform: scale(1.02); }
  .card-back.clickable { animation: pulse-border 1.5s ease-in-out infinite; }
  .card-back.clickable .click-hint { font-size: 0.55rem; color: rgba(255,255,255,0.95); text-align: center; line-height: 1.2; text-transform: uppercase; }
  @keyframes pulse-border { 0%, 100% { box-shadow: 0 0 0 0 rgba(26, 77, 109, 0.5); } 50% { box-shadow: 0 0 0 6px rgba(26, 77, 109, 0.2); } }
  .card-back.revealed { background: #fff; cursor: default; font-size: 1.25rem; flex-direction: row; }
  .card-back.revealed.red { color: #c00; }
  .add-row button { padding: 0.4rem 0.75rem; font-size: 1rem; cursor: pointer; }
  #add-btn:disabled { cursor: not-allowed; opacity: 0.6; }
</style>
<script src="algorithm.js"></script>
<script>
var pile = [];
var revealed = null;
var selectedRank = 2;
var selectedSuit = "c";

function selectedCardIsInPile() {
  return pile.some(function (card) {
    return card.rank === selectedRank && card.suit === selectedSuit;
  });
}

function updateAddButtonState() {
  var btn = document.getElementById("add-btn");
  btn.disabled = pile.length >= 4 || selectedCardIsInPile();
}

function addToPile() {
  if (pile.length >= 4 || selectedCardIsInPile()) return;
  pile.push({ rank: selectedRank, suit: selectedSuit });
  renderPile();
  updateAddButtonState();
  if (pile.length === 4) {
    var el = document.getElementById("fifth-card");
    el.classList.remove("revealed");
    el.classList.add("clickable");
    el.innerHTML = '<span class="click-hint">Click to reveal</span>';
    el.onclick = revealFifth;
    el.title = "Click to reveal your hidden card";
  }
}

function reset() {
  if (!revealed && !confirm("Clear all cards and start over?")) return;
  pile = [];
  revealed = null;
  selectedRank = 2;
  selectedSuit = "c";
  var el = document.getElementById("fifth-card");
  el.classList.remove("revealed", "clickable", "red");
  el.onclick = null;
  el.innerHTML = "";
  el.title = "Add 4 cards first";
  renderRankCards();
  renderSuitCards();
  renderPile();
  updateAddButtonState();
  document.getElementById("reset-btn").classList.remove("revealed");
}

function setRank(rank) {
  selectedRank = rank;
  document.querySelectorAll(".rank-card").forEach(function (el) {
    el.classList.toggle("selected", parseInt(el.getAttribute("data-rank"), 10) === rank);
  });
  updateAddButtonState();
}

function setSuit(suit) {
  selectedSuit = suit;
  document.querySelectorAll(".suit-card").forEach(function (el) {
    el.classList.toggle("selected", el.getAttribute("data-suit") === suit);
  });
  updateAddButtonState();
}

// Get the unicode character for a suit
function suitChar(suit) {
  if (suit === "c") return "\u2663";
  if (suit === "h") return "\u2665";
  if (suit === "s") return "\u2660";
  if (suit === "d") return "\u2666";
  return "";
}

function renderRankCards() {
  var numberRanks = [2, 3, 4, 5, 6, 7, 8, 9, 10];
  var faceRanks = [11, 12, 13, 1];  // Ace is low (= 1)
  var container = document.getElementById("rank-cards");
  container.innerHTML = "";
  function addRow(ranks) {
    var row = document.createElement("div");
    row.className = "rank-row";
    ranks.forEach(function (rank) {
      var card = document.createElement("div");
      card.className = "rank-card" + (rank === selectedRank ? " selected" : "");
      card.setAttribute("data-rank", rank);
      card.textContent = rankToShort(rank);
      card.onclick = function () { setRank(rank); };
      row.appendChild(card);
    });
    container.appendChild(row);
  }
  addRow(numberRanks);
  addRow(faceRanks);
}

function renderSuitCards() {
  var suitOptions = [
    { suit: "c", red: false },
    { suit: "h", red: true },
    { suit: "s", red: false },
    { suit: "d", red: true }
  ];
  var container = document.getElementById("suit-cards");
  container.innerHTML = "";
  suitOptions.forEach(function (option) {
    var card = document.createElement("div");
    card.className = "suit-card" + (option.red ? " red" : "") + (option.suit === selectedSuit ? " selected" : "");
    card.setAttribute("data-suit", option.suit);
    card.textContent = suitChar(option.suit);
    card.onclick = function () { setSuit(option.suit); };
    container.appendChild(card);
  });
}

function renderPile() {
  var container = document.getElementById("pile");
  container.innerHTML = "";
  for (var i = 0; i < 4; i++) {
    var slot = document.createElement("div");
    slot.className = "card-slot";
    if (i < pile.length) {
      var card = pile[i];
      slot.textContent = rankToShort(card.rank) + " " + suitChar(card.suit);
      if (card.suit === "h" || card.suit === "d") slot.classList.add("red");
    } else {
      slot.classList.add("empty");
      slot.textContent = "—";
    }
    container.appendChild(slot);
  }
}

// Face cards to short string (Ace = 1 low)
function rankToShort(rank) {
  if (rank === 1) return "A";
  if (rank <= 10) return rank;
  if (rank === 11) return "J";
  if (rank === 12) return "Q";
  if (rank === 13) return "K";
  return rank;
}

function revealFifth() {
  if (pile.length !== 4 || revealed) return;
  var rank1 = pile[0].rank, suit1 = pile[0].suit;
  var rank2 = pile[1].rank, suit2 = pile[1].suit;
  var rank3 = pile[2].rank, suit3 = pile[2].suit;
  var rank4 = pile[3].rank, suit4 = pile[3].suit;
  var result = computeHiddenCard(rank1, suit1, rank2, suit2, rank3, suit3, rank4, suit4);
  revealed = { rank: result.rank5, suit: result.suit5 };
  var el = document.getElementById("fifth-card");
  el.classList.add("revealed");
  el.classList.remove("clickable");
  el.onclick = null;
  el.textContent = rankToShort(revealed.rank) + " " + suitChar(revealed.suit);
  if (revealed.suit === "h" || revealed.suit === "d") el.classList.add("red");
  document.getElementById("reset-btn").classList.add("revealed");
}

</script>
</head>
<body>
<h1>AI Mind Reader</h1>
<p>Pick a rank and a suit, then add each of your four cards to the pile.</p>

<div class="picker">
  <div class="picker-section">
    <label>Rank</label>
    <div class="rank-cards" id="rank-cards"></div>
  </div>
  <div class="picker-section">
    <label>Suit</label>
    <div class="suit-cards" id="suit-cards"></div>
  </div>
  <div class="add-row">
    <button type="button" id="add-btn" onclick="addToPile()">Add to the pile</button>
  </div>
</div>

<p>Your cards:</p>
<div class="cards-row">
  <div id="pile" class="pile"></div>
  <div id="fifth-card" class="card-back" title="Add 4 cards first"></div>
</div>
<div class="reset-row">
  <button type="button" id="reset-btn" onclick="reset()">Start Over</button>
</div>

<footer>
  Adapted from Tim Muller's <a href="https://youtu.be/rkrjo4IIb1I" target="_blank" rel="noopener noreferrer">JavaScript Card Trick video</a>
  (his original version is <a href="http://magic.tinefamily.com/index_tim.html" target="_blank" rel="noopener noreferrer">here)</a>.<br>
  My code is available on <a href="https://github.com/steventine/javascript-card-trick" target="_blank" rel="noopener noreferrer">GitHub</a>.
</footer>

<script>
renderRankCards();
renderSuitCards();
renderPile();
updateAddButtonState();
</script>
</body>
</html>