W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>
body {
    margin: 0;
}
canvas {
    border:1px solid #d3d3d3;
    background-color: #f1f1f1;
}
</style>
</head>
<body onload="startGame()">
<script>
var myGamePiece;
var myUpBtn;
var myDownBtn;
var myLeftBtn;
var myRightBtn;

function startGame() {
    myGamePiece = new component(30, 30, "red", 10, 120);
    myUpBtn = new component(30, 30, "blue", 50, 10);    
    myDownBtn = new component(30, 30, "blue", 50, 70);    
    myLeftBtn = new component(30, 30, "blue", 20, 40);    
    myRightBtn = new component(30, 30, "blue", 80, 40);                
    myGameArea.start();
}

</script>

<p>Click on the blue "buttons" to make the red square move.</p>
</body>
</html>

​x
 
<!DOCTYPE html><html><head><meta name="viewport" content="width=device-width, initial-scale=1.0"/><style>body {    margin: 0;}canvas {    border:1px solid #d3d3d3;    background-color: #f1f1f1;}</style></head><body onload="startGame()"><script>var myGamePiece;var myUpBtn;var myDownBtn;var myLeftBtn;var myRightBtn;​function startGame() {    myGamePiece = new component(30, 30, "red", 10, 120);    myUpBtn = new component(30, 30, "blue", 50, 10);        myDownBtn = new component(30, 30, "blue", 50, 70);        myLeftBtn = new component(30, 30, "blue", 20, 40);        myRightBtn = new component(30, 30, "blue", 80, 40);                    myGameArea.start();}​​var myGameArea = {    canvas : document.createElement("canvas"),    start : function() {        this.canvas.width = 480;        this.canvas.height = 270;        this.context = this.canvas.getContext("2d");        document.body.insertBefore(this.canvas, document.body.childNodes[0]);        this.interval = setInterval(updateGameArea, 20);        window.addEventListener('mousedown', function (e) {            myGameArea.x = e.pageX;            myGameArea.y = e.pageY;        })        window.addEventListener('mouseup', function (e) {            myGameArea.x = false;            myGameArea.y = false;