Is there a way to have CSS3 transitions/animations for a div that’s just been added to/removed from the window or just has its style assigned? One scenario would be a tab control where the content has transitions when a tab header is clicked; this is normally done by assigning a different CSS style to the div that contains the content (without transition) that you want to display:
tabs-content > div{display:none;}
tabs-content > div.active{display:block;}
It occurred to me that most of the examples out there are using CSS3 transitions triggered by :hover.
CSS can’t be triggered like that. You’ll have to use JavaScript to either add a class to that element and let CSS animate it (I doubt it will work), or animate it directly with JavaScript.
I’d choose the latter.