HTML小游戲是一種非常有趣的程序代碼，通過HTML語言編寫，可以讓玩家在網頁上進行游戲。下面是一個基于HTML的小游戲程序代碼示例，包含如下幾個部分：

游戲規則：

玩家需要通過鍵盤控制小球躲避障礙物，每成功避開一個障礙物，得到一分，游戲結束條件為撞上障礙物。

var ballX = 50;
var ballY = 200;
var ballRadius = 10;
var ballColor = 'red';
var dx = 5;
var dy = -5;
var obstacleX = 600;
var obstacleY = 100;
var obstacleWidth = 50;
var obstacleHeight = 100;
var obstacleColor = 'blue';
var score = 0;
function drawBall() {
context.beginPath();
context.arc(ballX, ballY, ballRadius, 0, Math.PI * 2);
context.fillStyle = ballColor;
context.fill();
context.closePath();
}
function drawObstacle() {
context.beginPath();
context.rect(obstacleX, obstacleY, obstacleWidth, obstacleHeight);
context.fillStyle = obstacleColor;
context.fill();
context.closePath();
}
function drawScore() {
context.font = '16px Arial';
context.fillStyle = 'black';
context.fillText('Score: ' + score, 8, 20);
}
function moveBall() {
ballX += dx;
ballY += dy;
if (ballX + dx >canvas.width - ballRadius || ballX + dx< ballRadius) {
dx = -dx;
}
if (ballY + dy >canvas.height - ballRadius || ballY + dy< ballRadius) {
dy = -dy;
}
}
function moveObstacle() {
obstacleX -= 10;
if (obstacleX< -obstacleWidth) {
obstacleX = canvas.width;
obstacleY = Math.floor(Math.random() * (canvas.height - obstacleHeight));
score++;
}
}
function checkCollision() {
if (ballX + ballRadius >obstacleX && ballX - ballRadius< obstacleX + obstacleWidth && ballY + ballRadius >obstacleY && ballY - ballRadius< obstacleY + obstacleHeight) {
clearInterval(intervalId);
alert('Game Over! Your score is: ' + score);
}
}
function draw() {
context.clearRect(0, 0, canvas.width, canvas.height);
drawBall();
drawObstacle();
drawScore();
moveBall();
moveObstacle();
checkCollision();
}
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
var intervalId = setInterval(draw, 10);
document.addEventListener('keydown', function(event) {
if (event.keyCode == 38) {
dy = -5;
} else if (event.keyCode == 40) {
dy = 5;
}
});

以上代碼包括了小球，障礙物，分數以及鍵盤事件的控制等內容。玩家可以通過鍵盤控制小球的上下移動，躲避障礙物并得分。同時，代碼中還包括了碰撞檢測、定時器等功能。 通過HTML小游戲，玩家可以在網頁上獲得一段輕松愉快的娛樂。編寫HTML小游戲代碼能夠讓開發者鍛煉編寫項目的能力，提升編程技能水平。