var Ball = function () {
this.x = 100;
this.y = 100;
this.xSpeed = -2
this.ySpeed = 3;
};
var circle = function (x,y,radius,fillCircle) {
ctx.beginPath();
ctx.arc(x,y,radius,0,Math.PI * 2, false);
if (fillCircle) {
ctx.fill();
} else {
ctx.stroke();
}
};
Ball.prototype.draw = function() {
circle(this.x, this,y, 3, true);
};
Ball.prototype.move = function () {
this.x += this.xSpeed;
this.y += this.ySpeed;
};
Ball.prototype.checkCollision = function () {
if (this.x < 0 | | this.x > 200) {
this.xSpeed = -this.xSpeed;
}
if (this.y < 0 | |this.y > 200) {
this.ySpeed = -this.ySpeed;
}
};
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var ball = new Ball();
setInterval( function () {
ctx.clearRect(0,0,200,200);
ball.draw();
ball.move();
ball.checkCollision();
ctx.strokeRect(0,0,200,200);
}, 30)
