jStorage is a cross-browser key-value store database to store data locally in the browser - jStorage supports all major browsers, both in desktop (yes - even Internet Explorer 6) and in mobile.
jStorage is pretty small, about 8kB when minified.
Support jStorage development
Current availability: jStorage supports all major browsers - Internet Explorer 6+, Firefox 2+, Safari 4+, Chrome 4+, Opera 10.50+
If the browser doesn't support data caching, then no exceptions are raised - jStorage can still be used by the script but nothing is actually stored.
Project homepage and docs: www.jstorage.info