let y = 100;

let a = 34;

​

function setup() {

  createCanvas(700, 600);

}

​

function draw() {

  background(220);

  fill(31, 145, 87);

  ellipse(x, y, 100, 100);

  x++;

  y++;

  a--;

if (x < width) {

  console.log('ball on screen');

} else {

  console.log('ball off screen');

}

}

​