Simple Bouncing Ball

sketch.js

var balls = [];
var gravity = .1;

function setup() {
  createCanvas(windowWidth,windowHeight);
 
}

function draw() {
  background(255,255,255); 
  for (var i = 0; i < balls.length; i++) {
    balls[i].display();
  }

}

function mousePressed() {
  balls.push(new Ball());
}
var Ball = function() {
  this.x = mouseX;
  this.y = mouseY;
  this.speedY = 1;
  this.diameter = random(20,50);
}

Ball.prototype.display = function() {
  ellipse(this.x, this.y, this.diameter, this.diameter);
  this.y += this.speedY;

  if (this.y >= height) {
    this.speedY *= -.8;
  }

  this.speedY += gravity;
}