[lucb1e]

Not sure I understand. Numbers in JavaScript can't hold infinitely large numbers, so after a few squarings using x*x or Math.pow(x, 2) you're at float max (or at least lost some precision, breaking the proof) and would need to resort to custom code again rather than a hardware-accelerated browser-native operation.

[tromp]

He's talking about repeated squarings in a modular field, like integers mod N where N is the product of two large primes.