Whether this works or not depends on your CSS selectors being right, and on the AJAX request returning without error, and there's no way for us to know what exactly failed. The easiest way to find out would be to give us the URL to the page where you tried to implement that code.
But you're right, given you've done everything else correctly, it's as simple as that.
The buttons work absolutely fine for me. After clicking, the white box in the middle shows the title of the button, which is what the server returns.
Please describe what exactly is happening for you, what browser (version) you are using, and whether the AJAX request comes back with status "200 OK" (your debugger can tell you that).
Well for me it works in all browsers. If for you it doesn't, you have some debugging to do:
Is the DOM ready handler getting called at all?
If so, do those '#pdrNavWrapper img' elements exist ($('#pdrNavWrapper img').length)?
If so, does the click handler get called?
If so, is the AJAX call going out?
If so, is it coming back?
If so, without error?
If so, is the response being put into that div?
If so, is it visible?
If so, you see it, and you're finished.
That's nothing I can help you with, because I can't reproduce the issue.
Since you already changed it, I can't have a look why it didn't work. But I'm no magician either, so in order to find out why, I'd do exactly what I told you to do in my last post.
So, if you're really interested in the reason, please revert the change, so I can tell you, or debug it yourself.