How should I design this app?

I need to design a news reader开发者_StackOverflow社区 app,

This app must use HTML5

The problem is this app needs an archive function：

Auto download the news content from the server on schedule so that it can be read later when the phone is offline.

Anybody know how?

Could you explain why the has "must use HTML5" are you using a HTML Parser App builder E.G Phonegap ?

If so you might want to look at the Local Storage API this way you can download from a remote source parse what you need to from it then save the stuff you need into a array then serialize(JSON.encode) the array and store it into the local storage then load it from there, but there is a limit on local Storage size so you will have to remove all the stuff you dont want to keep any more so you only show the last 5 days or last 200 News Items.

if your not sure go look at http://www.phonegap.com (they have ducmentation) and if you build in that upload it to a GIT repo and they will download it and compile to all platforms supported by Phonegap the only big one they don't have is windows phone 7