jQuery removed $.support.leadingWhitespace from jquery greater 2.0
because support was dropped for IE 7/8. So if property is undefined,
we are pretty shure its ie > 8 or jQuery does not support the browser
fix browser detection for jQuery > 2.0
no confusing use of "!"
Thanks for the patch! Could you just add a comment above that line to explain the assumption, please? I want to avoid someone coming along later and breaking the logic because they don't understand why it's there.
add comment to browser detection