I have been recently developing mobile applications using a combination of HTML5, CSS3, Phonegap, and jQuery mobile. This is an amazing stack for developing portable mobile apps without the need to write native applications for each platform. The HTML5 spec, although not finalized is gaining wider and wider adoption and looks to transform mobile application development as well as the traditional web experience.
One of the great features of HTML5 is the ability to store data in the local browswer cache that’s much more robust then that previously afforded by HTTP cookies. There used to be a couple of ways to accomplish this. One was by using the WebSQL concept allowing data storage accessible thorough an SQL type syntax and hierarchal data structures. This method has been deprecated by the W3C (at least for now).
Here’s a trivial example…
You can download a simple working example of this principle here.
In the past, HTTP cookies have been used (some people might say misused) for the purpose of storing more or less persistent browser data. HTML5 local storage provides access to a datastore with much more capacity then that afforded by cookies. Local data caching can allow applications to be much more responsive and even operate in some cases when “offline”, a great capability in the world of mobile applications.