kedmundson · October 24, 2014 14:03
diff --git a/ticTacToe.html b/ticTacToe.html
 <html>
 <head>
  <title>Play Tic Tac Toe</title>
  <script src="ticTacToe.js"></script>
  <style>
    table {
      margin: 1% auto;
      border-collapse: collapse;
      width: 300px;
      height: 300px;
    }
    td {
      width: 33%;
      height: 33%;
      border-right: 5px solid #999;
      border-bottom: 5px solid #999;
      text-align: center;
      font: normal 4em Helvetica, sans-serif;
      color: #999;
    }
    td:last-child {
      border-right: 0;
    }
    tr:last-child > td {
      border-bottom: 0;
    }
  </style>
 </head>
 <body>
  <div id="ticTacToeBoard"></div>
 </body>
 </html>
diff --git a/ticTacToe.js b/ticTacToe.js
 // This is a game of Tic Tac Toe for two human players to play
 // in a browser. X begins each game.
 
 (function () {
 
  var playerX = { gamePiece: 'X', score: 0 }
    , playerO = { gamePiece: 'O', score: 0 }
    , currentPlayer
    , moves
    , movesLimit = 9
    , boxScore
    , boxes = []
 
    , createBoard = function () {
        newGame();
        var board = document.createElement('table')
          , row
          , box
          , boxScore = 1
          ;
 
        for (var i = 0; i < 3; i++) {
          row = document.createElement('tr');
          board.appendChild(row);
          for (var k = 0; k < 3; k++) {
            box = document.createElement('td');
            box.textContent = '';
            box.onclick = recordMove;
            //
            // Assign a unique score to each box, starting in the top left box
            // with boxScore = 1 and ascending in multiples of 2. This way we
            // can represent the boxes a player has marked with a bit string
            // and its corresponding numeral score, and check it against a
            // list of winning scores that we defined by adding the boxScores of
            // all the three-across, three-down, and three-diagonal combinations.
            // Credit for the bit string idea goes to this jsFiddle poster:
            // http://jsfiddle.net/5wKfF/
            //
            box.boxScore = boxScore;
            boxScore = (boxScore * 2);
            boxes.push(box);
            row.appendChild(box);
          }
        }
        document.getElementById('ticTacToeBoard').appendChild(board);
      }
 
    , winningScores = [ 7, 15, 56, 84, 146, 273, 292, 448 ]
 
    , recordMove = function () {
        if (this.textContent !== '') return;
        this.textContent = currentPlayer.gamePiece;
        currentPlayer.score += this.boxScore;
        moves += 1;
        if ( checkForWins(currentPlayer) || checkForTie() ) {
          return;
        } else {
          switchPlayer(currentPlayer);
        }
      }
 
    , checkForWins = function (player) {
        if (moves >= 5) {
          for (var i = 0; i < winningScores.length; i++) {
            //
            // Convert player.score and winningScores[i] to bit representations
            // and binary AND them using the '&' bitwise operator. If the two
            // operands match, the result will be the same as either operand
            // and therefore equal to winningScores[i]
            //
            // Using bits to represent an X or O in each box of the game board means that
            // this operation will work even if a player has marked more than three boxes
            // before getting a win.
            //
            if ((player.score & winningScores[i]) === winningScores[i]) {
              alert(player.gamePiece + " won! Do you want to play again?");
              newGame();
              return true;
            }
          }
        }
      }
 
    // End game in a tie if no one wins before movesLimit is reached       
    , checkForTie = function () {
        if (moves === movesLimit) {
          alert("It's a tie. Play again?");
          newGame();
          return true;
        }
      }
 
    , switchPlayer = function (player) {
        currentPlayer = (player === playerX) ? playerO : playerX;
      }
 
    // Reset the game board
    , newGame = function () {
        playerX.score = 0,
        playerO.score = 0,
        currentPlayer = playerX;
        moves = 0;
        for (var i = 0; i < boxes.length; i++) {
          document.getElementsByTagName('TD')[i].textContent = '';
        }
      }
 
    ;
 
  window.onload = function () {
    createBoard();
  }
 
 })();
	<html>
	<head>
	<title>Play Tic Tac Toe</title>
	<script src="ticTacToe.js"></script>
	<style>
	table {
	margin: 1% auto;
	border-collapse: collapse;
	width: 300px;
	height: 300px;
	}
	td {
	width: 33%;
	height: 33%;
	border-right: 5px solid #999;
	border-bottom: 5px solid #999;
	text-align: center;
	font: normal 4em Helvetica, sans-serif;
	color: #999;
	}
	td:last-child {
	border-right: 0;
	}
	tr:last-child > td {
	border-bottom: 0;
	}
	</style>
	</head>
	<body>
	<div id="ticTacToeBoard"></div>
	</body>
	</html>
	// This is a game of Tic Tac Toe for two human players to play
	// in a browser. X begins each game.

	(function () {

	var playerX = { gamePiece: 'X', score: 0 }
	, playerO = { gamePiece: 'O', score: 0 }
	, currentPlayer
	, moves
	, movesLimit = 9
	, boxScore
	, boxes = []

	, createBoard = function () {
	newGame();
	var board = document.createElement('table')
	, row
	, box
	, boxScore = 1
	;

	for (var i = 0; i < 3; i++) {
	row = document.createElement('tr');
	board.appendChild(row);
	for (var k = 0; k < 3; k++) {
	box = document.createElement('td');
	box.textContent = '';
	box.onclick = recordMove;
	//
	// Assign a unique score to each box, starting in the top left box
	// with boxScore = 1 and ascending in multiples of 2. This way we
	// can represent the boxes a player has marked with a bit string
	// and its corresponding numeral score, and check it against a
	// list of winning scores that we defined by adding the boxScores of
	// all the three-across, three-down, and three-diagonal combinations.
	// Credit for the bit string idea goes to this jsFiddle poster:
	// http://jsfiddle.net/5wKfF/
	//
	box.boxScore = boxScore;
	boxScore = (boxScore * 2);
	boxes.push(box);
	row.appendChild(box);
	}
	}
	document.getElementById('ticTacToeBoard').appendChild(board);
	}

	, winningScores = [ 7, 15, 56, 84, 146, 273, 292, 448 ]

	, recordMove = function () {
	if (this.textContent !== '') return;
	this.textContent = currentPlayer.gamePiece;
	currentPlayer.score += this.boxScore;
	moves += 1;
	if ( checkForWins(currentPlayer) \|\| checkForTie() ) {
	return;
	} else {
	switchPlayer(currentPlayer);
	}
	}

	, checkForWins = function (player) {
	if (moves >= 5) {
	for (var i = 0; i < winningScores.length; i++) {
	//
	// Convert player.score and winningScores[i] to bit representations
	// and binary AND them using the '&' bitwise operator. If the two
	// operands match, the result will be the same as either operand
	// and therefore equal to winningScores[i]
	//
	// Using bits to represent an X or O in each box of the game board means that
	// this operation will work even if a player has marked more than three boxes
	// before getting a win.
	//
	if ((player.score & winningScores[i]) === winningScores[i]) {
	alert(player.gamePiece + " won! Do you want to play again?");
	newGame();
	return true;
	}
	}
	}
	}

	// End game in a tie if no one wins before movesLimit is reached
	, checkForTie = function () {
	if (moves === movesLimit) {
	alert("It's a tie. Play again?");
	newGame();
	return true;
	}
	}

	, switchPlayer = function (player) {
	currentPlayer = (player === playerX) ? playerO : playerX;
	}

	// Reset the game board
	, newGame = function () {
	playerX.score = 0,
	playerO.score = 0,
	currentPlayer = playerX;
	moves = 0;
	for (var i = 0; i < boxes.length; i++) {
	document.getElementsByTagName('TD')[i].textContent = '';
	}
	}

	;

	window.onload = function () {
	createBoard();
	}

	})();