How can I add "load next 10 items" buttons on my iPhone webapp?

I have a webapp that is a gallery of pictures as well, but its starting to take a bit too long to load all of them in the initial loading of the webapp page. I have seen some webapps that have a button on the bottom of the page that says “load next 10 posts/pics/etc”. This would solve my problem, but I am not sure how this is accomplished, is there a tutorial or page that helps with this?