On Ajax loading

On Ajax loading

I'm gradually getting a handle on the whole jQM paradigm, but there are still some things that I haven't figured out.  I'm hoping that someone can help me...

1) jQuery Mobile loads subsequent pages via Ajax.  But what should those subsequent pages look like?  Full web pages with a head, etc?  Or just the <body> contents?

2) If ajax-loaded pages should be HTML fragments rather than entire documents, are there any request params that jQM sends, or can I somehow specify these parameters so that I can know to decorate pages differently depending on whether jQM is requesting them?

3) Is there any way to access the jQM-returned HTML before jQM turns it into virtual pages?

Thanks in advance for any help you can offer.

(I haven't found any really detailed documentation on how Ajax loading happens.  If there is a write-up on what's happening *in detail*, I'd love a pointer.)