Mobile Application - Need some help understanding the relevance of JQuery Mobile v/s Jquery

I have a bit of experience in creating web applications using asp.net however I am a complete newbie when it comes to creating mobile applications.

I am just embarking on my first mobile app and I have gotten a bit confused with all the various technologies/ frameworks out there and where they all fit in.

To take the example of a web application (which i am familiar with), the client side would be HTML + CSS + JS and the server side would be ASP.net / PHP / JSP or some such other combination. I have frequently used Jquery as my Javascript Framework.

My initial understanding with a mobile application was that I would use HTML5 + CSS + JS for the UI just like i would for a web application. Hence, it made sense to use JQuery again for the javascript programming.

However, i stumbled upon JQuery Mobile and though i browsed through some of the basic documentation on JQuery Mobile, i am at a loss to understand

Why 开发者_如何学JAVAis there a need for a separate JQuery framework for mobile apps and what does it offer that is different from JQuery? Also, if i am building a mobile app using the web standards of HTML 5, CSS 3 and JS, should i be using JQuery or JQuery Mobile?

If you're specifically targeting mobile devices, you have different requirements:

1. Touch UI
2. Smaller footprint (no need for all that IE-specific code)
3. Different browsers (Symbian? Blackberry?)

Those aren't things that are specifically addressed by jQuery, and since it has a different purpose, really shouldn't be.

Update: Apparently JQM is built on top of jQuery, so my statement about a smaller footprint is incorrect.