Resizing a Canvas

sketch.js

var canvas;
var middle;
var paddingAmount;

function setup() {
  canvas = createCanvas(windowWidth, windowHeight);
  canvas.parent('middle_panel');
  middle = select('#middle_panel');
  resizeCanvas(middle.width, middle.height);
}


function draw() {
  background(0);
  ellipse(width/2, height/2, 10, 10);
}

function windowResized() {
    middle = select('#middle_panel');
    resizeCanvas(middle.width, middle.height);
}