For clickable bar graphs, it may be easier to do it all in CSS and javascript. To spend your server time generating graphs (which I'm assuming the user might be able to change, which would require REgenerating the graph) seems a waste when you can offload the generation to the user's browser.

On top of that, you would have to figure out the image map to apply to the graph so that it becomes clickable.

No - HTML/CSS/javascript is the way to go here.

If you are developing for a closed user group and you know that they will be using Firefox/Mozilla/Opera/Safari, you could use the CANVAS tag which is designed specifically for this purpose.

clint