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Created November 6, 2018 07:03
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Basic Snake HTML Game
Raw
README.md

Basic Snake HTML Game

Snake is a fun game to make as it doesn't require a lot of code (less than 100 lines with all comments removed). This is a basic implementation of the snake game, but it's missing a few things intentionally and they're left as further exploration for the reader.

Further Exploration

  • Score
    • When the snake eats an apple, the score should increase by one. Use context.fillText() to display the score to the screen
  • Mobile and touchscreen support
  • Better apple spawning
    • Currently the apple spawns in any random grid in the game, even if the snake is already on that spot. Improve it so it only spanws in empty grid locations
Raw
snake.html
<!DOCTYPE html>
<html>
<head>
<title></title>
<style>
html, body {
height: 100%;
margin: 0;
}
body {
background: black;
display: flex;
align-items: center;
justify-content: center;
}
canvas {
border: 1px solid white;
}
</style>
</head>
<body>
<canvas width="400" height="400" id="game"></canvas>
<script>
var canvas = document.getElementById('game');
var context = canvas.getContext('2d');
var grid = 16;
var count = 0;
var snake = {
x: 160,
y: 160,
// snake velocity. moves one grid length every frame in either the x or y direction
dx: grid,
dy: 0,
// keep track of all grids the snake body occupies
cells: [],
// length of the snake. grows when eating an apple
maxCells: 4
};
var apple = {
x: 320,
y: 320
};
// get random whole numbers in a specific range
// @see https://stackoverflow.com/a/1527820/2124254
function getRandomInt(min, max) {
return Math.floor(Math.random() * (max - min)) + min;
}
// game loop
function loop() {
requestAnimationFrame(loop);
// slow game loop to 15 fps instead of 60 (60/15 = 4)
if (++count < 4) {
return;
}
count = 0;
context.clearRect(0,0,canvas.width,canvas.height);
// move snake by it's velocity
snake.x += snake.dx;
snake.y += snake.dy;
// wrap snake position horizontally on edge of screen
if (snake.x < 0) {
snake.x = canvas.width - grid;
}
else if (snake.x >= canvas.width) {
snake.x = 0;
}
// wrap snake position vertically on edge of screen
if (snake.y < 0) {
snake.y = canvas.height - grid;
}
else if (snake.y >= canvas.height) {
snake.y = 0;
}
// keep track of where snake has been. front of the array is always the head
snake.cells.unshift({x: snake.x, y: snake.y});
// remove cells as we move away from them
if (snake.cells.length > snake.maxCells) {
snake.cells.pop();
}
// draw apple
context.fillStyle = 'red';
context.fillRect(apple.x, apple.y, grid-1, grid-1);
// draw snake one cell at a time
context.fillStyle = 'green';
snake.cells.forEach(function(cell, index) {
// drawing 1 px smaller than the grid creates a grid effect in the snake body so you can see how long it is
context.fillRect(cell.x, cell.y, grid-1, grid-1);
// snake ate apple
if (cell.x === apple.x && cell.y === apple.y) {
snake.maxCells++;
// canvas is 400x400 which is 25x25 grids
apple.x = getRandomInt(0, 25) * grid;
apple.y = getRandomInt(0, 25) * grid;
}
// check collision with all cells after this one (modified bubble sort)
for (var i = index + 1; i < snake.cells.length; i++) {
// snake occupies same space as a body part. reset game
if (cell.x === snake.cells[i].x && cell.y === snake.cells[i].y) {
snake.x = 160;
snake.y = 160;
snake.cells = [];
snake.maxCells = 4;
snake.dx = grid;
snake.dy = 0;
apple.x = getRandomInt(0, 25) * grid;
apple.y = getRandomInt(0, 25) * grid;
}
}
});
}
// listen to keyboard events to move the snake
document.addEventListener('keydown', function(e) {
// prevent snake from backtracking on itself by checking that it's
// not already moving on the same axis (pressing left while moving
// left won't do anything, and pressing right while moving left
// shouldn't let you collide with your own body)
// left arrow key
if (e.which === 37 && snake.dx === 0) {
snake.dx = -grid;
snake.dy = 0;
}
// up arrow key
else if (e.which === 38 && snake.dy === 0) {
snake.dy = -grid;
snake.dx = 0;
}
// right arrow key
else if (e.which === 39 && snake.dx === 0) {
snake.dx = grid;
snake.dy = 0;
}
// down arrow key
else if (e.which === 40 && snake.dy === 0) {
snake.dy = grid;
snake.dx = 0;
}
});
// start the game
requestAnimationFrame(loop);
</script>
</body>
</html>
@harisonfekadu
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I embedded this game into a QR code. Check it out here!

@Grinzaza
Copy link

Grinzaza commented Feb 10, 2025 •
edited
Loading

add

  • start button
  • score
  • game over
<!DOCTYPE html>
<html lang="th">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Snake Game</title>
  <link href="https://fonts.googleapis.com/css2?family=Kanit:wght@400&display=swap" rel="stylesheet">
  <style>
    html, body {
      height: 100%;
      margin: 0;
      font-family: 'Kanit', sans-serif;
    }

    body {
      background: black;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
    }
    
    canvas {
      border: 1px solid white;
    }

    #start-button {
      margin-top: 20px;
      padding: 10px 20px;
      font-size: 16px;
      cursor: pointer;
    }

    #score {
      color: white;
      font-size: 18px;
      margin-top: 10px;
    }

    #game-over {
      color: red;
      font-size: 24px;
      display: none;
      margin-top: 20px;
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      z-index: 1;
    }
  </style>
</head>
<body>

<canvas width="400" height="400" id="game"></canvas>
<button id="start-button">Start</button>
<div id="score">Score: 0</div>
<div id="game-over">Game Over!</div>

<script>
var canvas = document.getElementById('game');
var context = canvas.getContext('2d');

var grid = 16;
var count = 0;

var snake = {
  x: 160,
  y: 160,
  dx: grid,
  dy: 0,
  cells: [],
  maxCells: 4
};

var apple = {
  x: 320,
  y: 320
};

var score = 0;

function getRandomInt(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

function loop() {
  requestAnimationFrame(loop);

  if (++count < 4) {
    return;
  }

  count = 0;
  context.clearRect(0, 0, canvas.width, canvas.height);

  snake.x += snake.dx;
  snake.y += snake.dy;

  if (snake.x < 0 || snake.x >= canvas.width || snake.y < 0 || snake.y >= canvas.height) {
    gameOver();
    return;
  }

  snake.cells.unshift({ x: snake.x, y: snake.y });

  if (snake.cells.length > snake.maxCells) {
    snake.cells.pop();
  }

  context.fillStyle = 'red';
  context.fillRect(apple.x, apple.y, grid - 1, grid - 1);

  context.fillStyle = 'green';
  snake.cells.forEach(function(cell, index) {
    context.fillRect(cell.x, cell.y, grid - 1, grid - 1);  

    if (cell.x === apple.x && cell.y === apple.y) {
      snake.maxCells++;
      score++;
      document.getElementById('score').innerHTML = 'Score: ' + score;
      
      apple.x = getRandomInt(0, 25) * grid;
      apple.y = getRandomInt(0, 25) * grid;
    }

    for (var i = index + 1; i < snake.cells.length; i++) {
      if (cell.x === snake.cells[i].x && cell.y === snake.cells[i].y) {
        gameOver();
      }
    }
  });
}

function gameOver() {
  document.getElementById('game-over').style.display = 'block';

  setTimeout(function() {
    location.reload();
  }, 500);
}

document.addEventListener('keydown', function(e) {
  if (e.which === 37 && snake.dx === 0) {
    snake.dx = -grid;
    snake.dy = 0;
  } else if (e.which === 38 && snake.dy === 0) {
    snake.dy = -grid;
    snake.dx = 0;
  } else if (e.which === 39 && snake.dx === 0) {
    snake.dx = grid;
    snake.dy = 0;
  } else if (e.which === 40 && snake.dy === 0) {
    snake.dy = grid;
    snake.dx = 0;
  }
});

document.getElementById('start-button').addEventListener('click', function() {
  requestAnimationFrame(loop);
});
</script>
</body>
</html>

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