Fastest modular exponentiation in JavaScript

Question

My problem is to compute (g^x) mod p quickly in JavaScript, where ^ is exponentiation, mod is the modulo operation. All inputs are nonnega

Answer 1

Why not do it server side in some kind of web service using a more appropriate language like C? Times will then be time for one round trip (less than 9 seconds), plus the time for the server to calculate the result using some BigInt library in native code. This is likely to be much faster.