jQuery Mobile: document ready vs. page events

I am using jQuery Mobile, and I am having trouble understanding differences between classic document ready and jQuery Mobile page events.

1. What is the real difference?

   Why should

   <!-- language: lang-js -->
   
   $(document).ready() {
   
   });
   

   be better than

   $(document).on('pageinit') {
   
   });
   

2. What is the order of page events, when you transition from one page to another?

3. How can I send data from one page to another and is it possible to access data from previous page?