In this tutorial, we will be creating a basic Tic Tac Toe game with HTML, CSS and JavaScript. **Python version: https://www.showwcase.com/show/14536/tic-tac-toe-with-python-tkinter-part-1** **Live demo: https://www.jothin.tech/tic-tac-toe/** ## The webpage 👀 Let's go ahead and create a GUI for the game. **Step 1:** Create webpage and add some CSS. - **index.html** ```html Tic Tac Toe

Tic Tac Toe

``` - **style.css** ``` body { position: absolute; text-align: center; top: 50%; left: 50%; transform: translate(-50%, -50%); padding: 10px; box-shadow: black 0 0 10px; } h1 { color: red; } #play-area { border: black solid 2px; overflow: hidden; } .square { width: 5em; height: 5em; float: left; border: black solid 1px; background-color: white; cursor: pointer; } .square:hover { background-color: orange; color: white; } ``` ![](https://project-assets.showwcase.com/8121/1647486477354-tic-tac-toe-9.gif) ![Tic Tac Toe with HTML, JS and CSS](https://project-assets.showwcase.com/8121/1647486477354-tic-tac-toe-9.gif) **Step 2:** Make the webpage functional with JavaScript. - **script.js** ```javascript let currentChr = "X"; let XPoint = []; let OPoint = []; class XOSquare { constructor(x, y, buttonId) { this.x = x; this.y = y; this.button = document.getElementById(buttonId); this.button.onclick = () => { this.set(buttonId) } } set(buttonId) { this.button = document.getElementById(buttonId); if (this.button.innerText === "") { this.button.innerText = currentChr; switchChr(); } } reset() { this.button.innerText = ""; } } function switchChr() { if (currentChr === "X") { currentChr = "O"; } else { currentChr = "X"; } } function setup() { let squares = []; let squareElements = document.getElementsByClassName("square"); for (let i = 0; i < squareElements.length; i++) { let square = new XOSquare(i % 3, Math.floor(i / 3), squareElements[i].id); squares.push(square); } } window.onload = setup; ``` Add this to **index.html** under **head** tag. ```html ``` ![Tic Tac Toe functional webpage interface with HTML, CSS and JavaScript](https://cdn.hashnode.com/res/hashnode/image/upload/v1647350472573/-Mozu1IX0.gif) ## Detect win and draw 🤔 Let's now implement a logic to detect win/draw. **Step 3:** Implement logic to detect win. We need to check after each move if X or O won the game. There are 8 possible ways in which one can win Tic Tac Toe: ![8 possible ways of winning Tic Tac Toe](https://cdn.hashnode.com/res/hashnode/image/upload/v1646563368479/YUL7azLEZ.png) Let's add some the JavaScript in **script.js** to detect game win. ```javascript let currentChr = "X"; let XPoint = []; let OPoint = []; class XOSquare { constructor(x, y, buttonId) { this.x = x; this.y = y; this.button = document.getElementById(buttonId); this.button.onclick = () => { this.set(buttonId) } } set(buttonId) { this.button = document.getElementById(buttonId); if (this.button.innerText === "") { this.button.innerText = currentChr; if (currentChr === "X") { XPoint.push(this); } else { OPoint.push(this); } switchChr(); checkWin(); } } reset() { this.button.innerText = ""; } } class winningPossibility { constructor(x1, y1, x2, y2, x3, y3) { this.x1 = x1; this.y1 = y1; this.x2 = x2; this.y2 = y2; this.x3 = x3; this.y3 = y3; } } function checkWinningPossibility(winningPossibility, forChr) { let p1Satisfied = false; let p2Satisfied = false; let p3Satisfied = false; if (forChr === 'X') { for (let i = 0; i < XPoint.length; i++) { if (XPoint[i].x === winningPossibility.x1 && XPoint[i].y === winningPossibility.y1) { p1Satisfied = true; } else if (XPoint[i].x === winningPossibility.x2 && XPoint[i].y === winningPossibility.y2) { p2Satisfied = true; } else if (XPoint[i].x === winningPossibility.x3 && XPoint[i].y === winningPossibility.y3) { p3Satisfied = true; } } } else { for (let i = 0; i < OPoint.length; i++) { if (OPoint[i].x === winningPossibility.x1 && OPoint[i].y === winningPossibility.y1) { p1Satisfied = true; } else if (OPoint[i].x === winningPossibility.x2 && OPoint[i].y === winningPossibility.y2) { p2Satisfied = true; } else if (OPoint[i].x === winningPossibility.x3 && OPoint[i].y === winningPossibility.y3) { p3Satisfied = true; } } } return p1Satisfied && p2Satisfied && p3Satisfied; } const winningPossibilities = [ new winningPossibility(1, 1, 1, 2, 1, 3), new winningPossibility(2, 1, 2, 2, 2, 3), new winningPossibility(3, 1, 3, 2, 3, 3), new winningPossibility(1, 1, 2, 1, 3, 1), new winningPossibility(1, 2, 2, 2, 3, 2), new winningPossibility(1, 3, 2, 3, 3, 3), new winningPossibility(1, 1, 2, 2, 3, 3), new winningPossibility(3, 1, 2, 2, 1, 3) ] function checkWin() { for (let i = 0; i < winningPossibilities.length; i++) { if (checkWinningPossibility(winningPossibilities[i], 'X')) { console.log("X wins"); return; } if (checkWinningPossibility(winningPossibilities[i], 'O')) { console.log("O wins"); return; } } } function setup() { let squares = []; let squareElements = document.getElementsByClassName("square"); for (let i = 0; i < squareElements.length; i++) { let square = new XOSquare(i % 3 + 1, Math.floor(i / 3) + 1, squareElements[i].id); squares.push(square); } } ``` ![Tic Tac Toe interface with HTML, CSS and JS](https://cdn.hashnode.com/res/hashnode/image/upload/v1647351570648/yJORhfNkG.gif) When X or O wins the game, console.log is triggered. **Step 4:** Detect draw. Append the following code to function "checkWin" in **script.js** ```javascript if (XPoint.length + OPoint.length === 9) { console.log("Draw"); } ``` ## Enhancements **Step 5:** Add a status label and use it instead of console.log Let's make a few changes to **script.js**: - function **"switchChr"**: ```javascript function switchChr() { const statusLabel = document.getElementById("status"); if (currentChr === "X") { currentChr = "O"; statusLabel.innerText = "O's turn"; } else { currentChr = "X"; statusLabel.innerText = "X's turn"; } } ``` - function **"checkWin"**: ```javascript function checkWin() { const statusLabel = document.getElementById("status"); for (let i = 0; i < winningPossibilities.length; i++) { if (checkWinningPossibility(winningPossibilities[i], 'X')) { statusLabel.innerText = "X wins"; disableGame(); return; } if (checkWinningPossibility(winningPossibilities[i], 'O')) { statusLabel.innerText = "O wins"; disableGame(); return; } } if (XPoint.length + OPoint.length === 9) { statusLabel.innerText = "Draw"; disableGame(); } } ``` Add this new element in **index.html** under body tag ```html

X's turn

``` Add the following to **style.css** ```css #status { color: green; } ``` ![Tic Tac Toe with HTML, CSS and JS with status label](https://cdn.hashnode.com/res/hashnode/image/upload/v1647352737325/6eqi3M0Kz.gif) **Step 6:** Play again Let's add a play again button so that we don't need to refresh the webpage if we want to replay. We need to create new functions in **script.js** - function "playAgain" ```javascript function playAgain() { const buttons = document.getElementsByClassName("square"); for (let i = 0; i < buttons.length; i++) { buttons[i].disabled = false; buttons[i].innerText = ""; } XPoint = []; OPoint = []; currentChr = "X"; const statusLabel = document.getElementById("status"); statusLabel.innerText = "X's turn"; const playAgainButton = document.getElementById("play-again"); playAgainButton.style.display = "none"; } ``` - function "disableGame": ```javascript function disableGame() { const buttons = document.getElementsByClassName("square"); for (let i = 0; i < buttons.length; i++) { buttons[i].disabled = true; } const playAgainButton = document.getElementById("play-again"); playAgainButton.style.display = "block"; } ``` Add this element to **index.html** under body tag: ```html ``` Add this property to **#play-area** in **style.css**: ```css margin-bottom: 10px; ``` Add some css for **#play-again** (play again button) in **style.css**: ```css #play-again { box-shadow: black 0 0 5px; margin: auto; display: none; } ``` **Step 7:** Theme switch. A webpage won't be complete without a cool theme switch. So, let's add one! Add the following JS code to **script.js**: ```javascript let currentTheme = 'light'; function switchTheme() { if (currentTheme === 'dark') { document.querySelectorAll('.dark-mode').forEach(function (element) { element.classList.remove('dark-mode'); element.classList.add('light-mode'); }); currentTheme = 'light'; } else { document.querySelectorAll('.light-mode').forEach(function (element) { element.classList.remove('light-mode'); element.classList.add('dark-mode'); }); currentTheme = 'dark'; } } ``` Let's rewrite the CSS: ```css body.light-mode { position: absolute; text-align: center; top: 50%; left: 50%; transform: translate(-50%, -50%); padding: 10px; box-shadow: black 0 0 10px; } h1.light-mode { color: red; } #status.light-mode { color: green; } #play-area.light-mode { border: black solid 2px; overflow: hidden; margin-top: 10px; margin-bottom: 10px; } .square.light-mode { width: 5em; height: 5em; float: left; border: black solid 1px; background-color: white; cursor: pointer; } .square.light-mode:hover { background-color: orange; color: white; } .square.clicked.light-mode { background-color: red; color: white; } #play-again.light-mode { box-shadow: black 0 0 5px; margin: auto; display: none; } body.dark-mode { position: absolute; text-align: center; top: 50%; left: 50%; transform: translate(-50%, -50%); padding: 10px; box-shadow: white 0 0 10px; background: black; } h1.dark-mode { color: white; } #status.dark-mode { color: blue; } #play-area.dark-mode { border: white solid 2px; overflow: hidden; margin-top: 10px; margin-bottom: 10px; } .square.dark-mode { width: 5em; height: 5em; float: left; border: white solid 1px; background-color: black; color: white; cursor: pointer; } .square.dark-mode:hover { background-color: gray; color: white; } #play-again.dark-mode { box-shadow: black 0 0 5px; margin: auto; display: none; } ``` Let's change the body tag in **index.html**: ```html

Tic Tac Toe

X's turn

``` ![Tic Tac Toe with HTML, CSS and JS theme switch](https://cdn.hashnode.com/res/hashnode/image/upload/v1647453110816/FqujNgEot.gif) **Full code available at GitHub repository: https://github.com/Jothin-kumar/tic-tac-toe** **Live demo: https://www.jothin.tech/tic-tac-toe/** If you find this article useful, drop a like ⭐ and follow me to get all my latest content.