A random number generator in JavaScript without using a Math.random function is a challenge to write. Much research has gone into the theoretical underpinnings of such a procedure but I have not been able to fathom any of it till now. That can be a future endeavour I suppose.

For the present I am using the random number generator presented in Knuth's The Art Of Computer Programming: Seminumerical Algorithms (Vol 2). It's a port from the C code with the essential parts modified. The original code can be found at http://www-cs-faculty.stanford.edu/~uno/programs/rng-double.c View the demo to see it in action.

Here is the code: