Recently I have read very good article on Lazy Loading Collapsible panel in ASP.NET Using JSON.
Satheesh babu has written a very good article on this. I hope it can help you to increase your jQuery skill.
In collapsible panel we fully load the contents when the page is initially rendered to the client. Hence, clicking the arrow buttons on the panel will just expand and collapse the contents. This will make the page heavy when there are large amount of data on different panels on the page. It will be better and light weight when we actually load the contents of the panels only when the user clicks the expand arrow button, a lazy loading or loading on-demand.
Read full article : here
Hope this will helps !!!