<div id="sketch-holder">
      <!-- Our sketch will go here! -->
    </div>
<script>
function setup() {
  var canvas = createCanvas(640, 480);
  canvas.parent('sketch-holder');
}

function draw() {
  if (mouseIsPressed) {
    fill(0);
  } else {
    fill(255);
  }
  ellipse(mouseX, mouseY, 80, 80);
}
  
  
</script>