Simple collision system update

gistfile1.js

function SimpleCollisionSystem() {
  this.update = function update() {
    for(var a = 0; a < this.circles.length; a++) {
      var circle1 = this.circles[a];
  
      //n * n/2 loop to check for collisions on every other particle
      for(var b = a + 1; b < this.circles.length; b++) {
        var circle2 = this.circles[b];
  
        circle1.checkCollisionOnAnotherCircle(circle2);
      }
  
      circle1.move(); //"walk" the particle
      //check for collisions on the canvas border
      circle1.checkCollisionOnX(this.canvas.width);
      circle1.checkCollisionOnY(this.canvas.height);
    }
  }
}