jQuery - Animate css background-size?

I'm trying to animate the size of my background image, but it's not working - Any idea why from the following code?

$(this).animate({'opacity' : 1, 'backgr开发者_Python百科ound-size':'70px 48px', 'right':39, 'top':45}, 250);

Note: all the other properties animate correctly, it's just the background-size that doesn't update.

Thanks!

Because background-size is a CSS3 property that is not supported by jQuery yet as it's still a candidate for recommendation.

See this plugin.

Old link chain forwards to this plugin But it's quite hard to find function that answers this question.