h5bp/html5please — pull request #75 by jensarps (2012-01-24 09:50:55+00:00)
Title: Change safe-to-assume size to 2.5MB for localStorage

In webkit based browsers, desktop as well as mobile, localStorage is sadly only 2.5MBs.

This seems to be due to UTF-16 encoding, see this bug:

http://code.google.com/p/chromium/issues/detail?id=58985#c15

Here's a sweet list of browserscope results for a size test that confirms this:

http://dev-test.nemikor.com/web-storage/support-test/