the limits of AJAX?

the limits of AJAX?

I'm working on several new sites. I'd like to AJAXify as much as possible. I use PHP to generate JSON data from my MySQL tables and with jQuery's getJSON I then pass them to DIV's on the site. This is all very nice, but now I have a problem. The contents of the DIV's seem to be unaware of things like mouse clicks, hovers and the likes. So despite the fact that I defined the CSS ID's and wrote some jQuery code there's no response. I think it has something to do with document.ready (the content is placed after the DOM has finished).
Is there a way to circumvent this nasty problem (ie. I'm doing something wrong), or is it a limitation of the whole method (MySQL -> PHP -> JSON -> HTML/CSS)... I hope the problem I have is clear and there's someone with more knowledge than me that can shine a light on this subject.