Another feature test – for full support of the most modern flexbox syntax (excluding buggy IE10):
var root = document.documentElement.style, flexsupport = 'flexWrap' in root || 'WebkitFlexWrap' in root;
I did not mean to limit the topic to JS by the way. Anything that qualifies as clean and nifty will do.
And I thought I’d mark bearhead’s second contribution after all but there seems to be a time limit on that…