javascript中Math.random的替代方案

var array = new Uint32Array(1);
window.crypto.getRandomValues(array);
var randomNum = array[0] / (Math.pow(2, 32) - 1);

var randomNum = Date.now() % 1;

function customRandom() {
  var x = 123456789;
  var y = 987654321;
  var z = new Date().getTime();
  var w = 987654321;
  var t;

  return function() {
    t = x ^ (x << 11);
    x = y;
    y = z;
    z = w;
    w = (w ^ (w >>> 19)) ^ (t ^ (t >>> 8));
    return w / (Math.pow(2, 32) - 1);
  };
}

var randomFunc = customRandom();
var randomNum = randomFunc();