Chrome 23 on Mac. Still happening with FF, even after upgrading to 17.0. FF's "Unresponsive script" alert box mentions line 103.

It's not just loops that can trigger this stuff. It's also callbacks that trigger the same callbacks.

It's the "while (!done)" loop. next(2012-09-24) returns the same date. Not sure why yet.

Your date arithmetic jumps through some weird hoops to accomplish something really simple. To increment a date by one day, for example, can be done like so:

      d = new Date(base);
      d.setDate(d.getDate() + 1);

Changing rel() to do this fixes the loop problem, but something else is surely wrong, because the result page now looks like this: http://i.imgur.com/ZUAJg.png