Data Load only appear after Page_Load event (asp .net)

I have a page that takes too much time to load because it fetches from database a large amount of data. I would need someone to change the page in order too: when the page loads for the first time it shows immediately the page structure (without any data) and only after this it fetches the data from database and sets the fields with the info. Would be a must if it can show the progress of data load. Currently the page uses jquery and Ajax. And is is asp.net.