browser.js

module.exports = (function (global) {
  var uint32 = 'Uint32Array' in global
  var crypto = global.crypto || global.msCrypto
  var rando = crypto && typeof crypto.getRandomValues === 'function'
  var good = uint32 && crypto && rando
  if (!good) return Math.random

  var arr = new Uint32Array(1)
  var max = Math.pow(2, 32)
  function random () {
    crypto.getRandomValues(arr)
    return arr[0] / max
  }

  random.cryptographic = true
  return random
})(typeof self !== 'undefined' ? self : window)