Possible Duplicate:
How to create my own JavaScript Random Number generator that I can also set the seed
Is there any random number generator for Javascript?
Before you say Math.random(), my requirement is that it should allow a seed value. For the same seed value it should generate the exact same sequence of 'random' numbers, and the number sequence should be fairly random.
Sorry, this has just gotta be done:
function makeRandom(seed) {
var next = 4; // chosen by fair dice roll.
// guaranteed to be random
return function() {
return seed + next++;
};
}
Usage:
var random = makeRandom(492347239);
var r1 = random();
var t2 = random();
...
Credit: http://xkcd.com/221/
NB: to make it actually useful, replace the returned function with a generic PRNG such as ARC4. The real purpose of the code above is to show how you can encapsulate state (i.e. the current seed) in a closure and repeatedly obtain successive values from that object.
