On my Drupal site I have a block which I've set up with a couple of links at the top.
I want to change the content of the block depending on which link is clicked.
I'm pretty sure you can do this as I've seen sites with this functionality, but I'm not sure how to accomplish it.
The problem, as I see it, is that the PHP code which controls that block content is server side and the clicking of the links is browser side.