The Window.crypto read-only property returns the Crypto object associated to the global object. This object allows web pages access to certain cryptographic related services.
var cryptoObj = window.crypto || window.msCrypto; // for IE 11
Window.crypto property to access the getRandomValues() method.genRandomNumbers = function getRandomNumbers() {
  var array = new Uint32Array(10);
  window.crypto.getRandomValues(array);
 
  var randText = document.getElementById("myRandText");
  randText.innerHTML = "The random numbers are: "
  for (var i = 0; i < array.length; i++) {
    randText.innerHTML += array[i] + " ";
  }
} <p id="myRandText">The random numbers are: </p> <button type="button" onClick='genRandomNumbers()'>Generate 10 random numbers</button>
| Specification | Status | Comment | 
|---|---|---|
| Web Cryptography API The definition of 'Window.crypto' in that specification.  |  Recommendation | Initial definition | 
| Desktop | ||||||
|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
| Basic support | 37 | 12 | 34 |  11
  | 
24 | 6.1 | 
| Mobile | |||||||
|---|---|---|---|---|---|---|---|
| Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
| Basic support | 37 | 37 | 12 | 34 | 24 | 6.1 | Yes | 
Window global object
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
    https://developer.mozilla.org/en-US/docs/Web/API/window/crypto