Detecting if browser will use CSS

I want to do different DocType if not CSS

[abigailr]

How could I detect if browser will use CSS?
I want to do different DocType if not CSS.
The reason I want to do this is I currently have a Table layout which works great but it won't validate with HTML5. So I want to keep my table layout when there is no CSS and design a new layout for HTML5.

Here are the hosting specs:
Apache version 2.2.21
PHP version 5.2.17
MySQL version 5.0.96-community-log

[swa66]

There is no browser actively used that's not going to do CSS.

Even the very few special browsers (like those used to show braille, read out text, or pure text based browsers) will work a lot better it you forget about abusing tables for layout.

Just remove the tables and go for semantic markup in html and CSS for layout.

[lucy24]

And besides...

The validator by itself doesn't know that you are using the tables for layout. So you're doing something else wrong. And it's likely to become even more visibly wrong if you disable the CSS.