Is it possible to format an HTML tooltip?
E.g. I have a DIV with attribute title="foo!". When I have text-size of my browser zoomed in or out in, the text size of the tooltip remains unchanged. Is there a way to make the tooltip font scale with the browser setting?
No. But there are other options out there like Overlib, and jQuery that allow you this freedom.
Personally, I would suggest jQuery as the route to take. It's typically very unobtrusive, and requires no additional setup in the markup of your site (with the exception of adding the jquery script tag in your <head>).