This is good news. I had high hopes for HTML5. But when Google decided to fork HTML5, I was concerned that Safari might fall behind. Or at the least, we'd be end up with the old browser wars where web pages would looks completely different from browser to browser. I wish they'd just all play nice together. With Apple incorporating support for Mozilla's JS, maybe there's hope...
Playing nice is not in the best interest of all parties involved, so until a standard is set, then this will continue.