HTML5: is it possible?

Hi,
I have been working with HTML and CSS for a long time now but I am a newbie in HTML5 and mobile devices.
I want to know the following before starting a project:

  1. Is it possible to create an HTML5 application that:

a. detects the type mobile device and loads specific layout/functionality according to that?
b. stores data (maybe through xml or in a database? what language can I use for that? php?)
c. works offline as well - but where does it store the data during this? How does it sync when it gets connected
d. provides drag and drop features on a touch device

  1. If it is possible, what is the level of difficulty?
  2. Are there any specific mobile platforms you would recommend I can work with (not heavy programming)
  3. Are there any specific resources, tutorials, APIs that can help me towards this direction?

Thanks
Kadjia

1
a. Yes, with the help of CSS3 media queries you can do so. It will detect the screen size and the pixel density ratio of the device and will load functionalities accordingly.
b. Yes, you can store the data using Web SQL database and the language should be JavaScript.
c. To present the data offline, you will have to use the Web SQL database to store all the data .
d. With the help of Javascript you can create an HTML5 application that provides drag and drop features. jQuery might also be considered.

2 It is a bit complex thing to do. But, not impossible.

3 What do you mean here ?

4 Use Google.