What tool can analyze my site and report on unused / unneeded CSS?

Question

how can i find in a early way that this css class is being used or not in website ?

like-

style property that i write in my css is being used or not?

Answer 1

There's also "Dust-Me", a firefox extension to find unused CSS:

https://addons.mozilla.org/en-US/firefox/addon/5392/

However this plugin doesn't work with FF5+