I would like an updated version of the above. He's made improvements upon the implementation: [quote:1c871dbq]
Update 11/10/2013: I am getting ready to release a version 2.3 (same random sequence) designed to be slightly friendlier to use in node.js, and I got a chance to test the PRNG quality using the dieharder random number test suite, which collects billions of outputs and tests for non-random patterns. To provide input data to dieharder, I just called seedrandom from node.js and tested the output stream of 32-bit numbers generated by Math.floor(Math.random() * 4294967296).
Here is the dieharder analysis of the sequence starting with Math.seedrandom(1). Note that the "WEAK" asessment is given for tests that result in a p that is near zero or near one, but because more than a hundred tests were run, we expect occasional tests to come in big or small - indeed if no tests were reported "WEAK", it would be an indication of a problem. Overall, the performance of this little javascript PRNG is pretty robust.
Update 1/1/2014: seedrandom is now available as a package in npm and bower. The current version number is 2.3.1.