You should use/wrap the web crypto api[0] where available[1].
var crypto = window.crypto || window.msCrypto; // for IE 11
var array = new Uint32Array(10);
crypto.getRandomValues(array);
Uint32Array should now be filled with cryptographically sound random numbers. There are JS based algorithms that generate better random numbers than Math.Random, but polyfills are a bit heavy.
If you're using webpack/browserify, the crypto library's random is polyfilled, which you can use safely.
[0] https://developer.mozilla.org/en-US/docs/Web/API/Window/crypto
[1] http://caniuse.com/#feat=cryptography
You should use/wrap the web crypto api[0] where available[1]. var crypto = window.crypto || window.msCrypto; // for IE 11 var array = new Uint32Array(10); crypto.getRandomValues(array); Uint32Array should now be filled with cryptographically sound random numbers. There are JS based algorithms that generate better random numbers than Math.Random, but polyfills are a bit heavy. If you're using webpack/browserify, the crypto library's random is polyfilled, which you can use safely. [0] https://developer.mozilla.org/en-US/docs/Web/API/Window/crypto [1] http://caniuse.com/#feat=cryptography