Collisions when generating UUIDs in JavaScript

Indeed there are collisions, but only under Google Chrome. Check out my experience on the topic in Google Chrome random number generator issue

It seems like collisions only happen on the first few calls of Math.random. Because if you just run the createGUID / testGUIDs method above (which obviously was the first thing I tried), it just works without any collisions whatsoever.

So to make a full test one needs to restart Google Chrome, generate 32 byte, restart Chrome, generate, restart, generate, etc.

My best guess is that Math.random() is broken on your system for some reason (bizarre as that sounds). This is the first report I've seen of anyone getting collisions.

node-uuid has a test harness that you can use to test the distribution of hex digits in that code. If that looks okay then it's not Math.random(), so then try substituting the UUID implementation you're using into the uuid() method there and see if you still get good results.

[Update: Just saw Veselin's report about the bug with Math.random() at startup. Since the problem is only at startup, the node-uuid test is unlikely to be useful. I'll comment in more detail on the devoluk.com link.]