[css3-images] browser support

Hello CSS working group,
                                      I was looking through the latest draft
for CSS3 images and I was trying to implement and test some of the proposed
and drafted features
I was wondering and hoping if someone could answer a few questions I had
after reading the Editor's draft published on the 15th of December, 2010.

In regards to gradients, I could not get them to work in the latest versions
of Webkit or Mozilla Firefox.
Was there an error in my styling:
..gradientBox{
                        background:linear-gradient(#f5f5f5, #d3d3d3);
}

or are css3 gradients, the non vendor specific version, as introduced in the
draft not yet supported by any browser? If so, do you have an estimate when
it might be supported in common browsers? And, finally, is there a method or
browser I can use to test these new features and others?

Thanks in Advance & Best Regards,
                                                       Irfan Mir

P.S. The reason why I do not prefer vendor-specific styling is that it is
vendor-specific and it does not validate in the W3C's CSS validation test.
Speaking of which, would the linear-gradient / radial-gradient validate or
not, I am assuming it would not due to its draft status? In other words,
does styling have to be out of draft and recommended for use to validate?