Are you using Firebug or Venkman? Did you ever tried the Chrome developer tools? If your answers were yes and no you should watch this video from Google IO 2011 about the Chrome developer tools:
If your answers were no and no you should consider watching the video, too. And
you should think about better ways than sprinkling alert() all over
you’re code and forget them there for the joy of the user.
The CSS3 patterns mentioned in the video you can find here.