HTML Game Example

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Learn how to make games, using nothing but HTML and JavaScript.

Push the buttons to move the red square:

var myGameArea;
var myGamePiece;
var myObstacles = ;
var myscore;

function restartGame() {
document.getElementById("myfilter").style.display = "none";
document.getElementById("myrestartbutton").style.display = "none";
myGameArea.stop();
myGameArea.clear();
myGameArea = {};
myGamePiece = {};
myObstacles = ;
myscore = {};
document.getElementById("canvascontainer").innerHTML = "";
startGame()
}

function startGame() {
myGameArea = new gamearea();
myGamePiece = new component(30, 30, "red", 10, 75);
myscore = new component("15px", "Consolas", "black", 220, 25, "text");
myGameArea.start();
}

function gamearea() {
this.canvas = document.createElement("canvas");
this.canvas.width = 320;
this.canvas.height = 180;
document.getElementById("canvascontainer").appendChild(this.canvas);
this.context = this.canvas.getContext("2d");
this.pause = false;
this.frameNo = 0;
this.start = function() {
this.interval = setInterval(updateGameArea, 20);
}
this.stop = function() {
clearInterval(this.interval);
this.pause = true;
}
this.clear = function(){
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
}
}

function component(width, height, color, x, y, type) {

this.type = type;
if (type == "text") {
this.text = color;
}
this.score = 0; this.width = width;
this.height = height;
this.speedX = 0;
this.speedY = 0;
this.x = x;
this.y = y;
this.update = function() {
ctx = myGameArea.context;
if (this.type == "text") {
ctx.font = this.width + " " + this.height;
ctx.fillStyle = color;
ctx.fillText(this.text, this.x, this.y);
} else {
ctx.fillStyle = color;
ctx.fillRect(this.x, this.y, this.width, this.height);
}
}
this.crashWith = function(otherobj) {
var myleft = this.x;
var myright = this.x + (this.width);
var mytop = this.y;
var mybottom = this.y + (this.height);
var otherleft = otherobj.x;
var otherright = otherobj.x + (otherobj.width);
var othertop = otherobj.y;
var otherbottom = otherobj.y + (otherobj.height);
var crash = true;
if ((mybottom otherbottom) || (myright otherright)) {
crash = false;
}
return crash;
}
}

function updateGameArea() {
var x, y, min, max, height, gap;
for (i = 0; i < myObstacles.length; i += 1) {
if (myGamePiece.crashWith(myObstacles[i])) {
myGameArea.stop();
document.getElementById("myfilter").style.display = "block";
document.getElementById("myrestartbutton").style.display = "block";
return;
}
}
if (myGameArea.pause == false) {
myGameArea.clear();
myGameArea.frameNo += 1;
myscore.score +=1;
if (myGameArea.frameNo == 1 || everyinterval(150)) {
x = myGameArea.canvas.width;
y = myGameArea.canvas.height - 100;
min = 20;
max = 100;
height = Math.floor(Math.random()*(max-min+1)+min);
min = 50;
max = 100;
gap = Math.floor(Math.random()*(max-min+1)+min);
myObstacles.push(new component(10, height, "green", x, 0));
myObstacles.push(new component(10, x - height - gap, "green", x, height + gap));
}
for (i = 0; i < myObstacles.length; i += 1) {
myObstacles[i].x += -1;
myObstacles[i].update();
}
myscore.text="SCORE: " + myscore.score;
myscore.update();
myGamePiece.x += myGamePiece.speedX;
myGamePiece.y += myGamePiece.speedY;
myGamePiece.update();
}
}

function everyinterval(n) {
if ((myGameArea.frameNo / n) % 1 == 0) {return true;}
return false;
}

function moveup(e) {
myGamePiece.speedY = -1;
}

function movedown() {
myGamePiece.speedY = 1;
}

function moveleft() {
myGamePiece.speedX = -1;
}

function moveright() {
myGamePiece.speedX = 1;
}

function clearmove(e) {
myGamePiece.speedX = 0;
myGamePiece.speedY = 0;
}
startGame();

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Try it Yourself Examples

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