Local Storage under Sub-domain

I am writing a user script which use Local Storage to save users' setting. As local storage i开发者_高级运维s unique for each domain, how can I share the Local Storage between example.com and www.example.com?

The easiest way to avoid the problem - just don't use both non-www and www domain names at once, you should choose one and do permanent redirect from second one. The reasons for this are not only connected with local storage, the main issue here is search engine optimisation.