mandelbrotRank.js

function mandelbrotRank (timeout, x, y) {
  var i = 0,
    zx = x,
    zy = y;

  while (zx*zx + zy*zy < 4 && i < timeout){
    var tx = zx*zx - zy*zy + x,
      ty = 2*zx*zy + y;

    zx = tx;
    zy = ty;

    i += 1;
  }

  return i;
}