Hi,
I've tried latest 1.18.0 release, sadly the patch #2142 for bug #2141 introduced a bad regression on (at least) IE11, because validation doesn't work anymore!

The culprit is following code path in jquery.validate.js:

		if ( element.isContentEditable ) {
			val = $element.text();
		} else {
			val = $element.val();
		}

When you try my code example at https://liveweave.com/N6xRPw using latest Chrome or Firefox, validation works correctly because element.isContentEditable is false.
But when you use IE11, element.isContentEditable seems to be always true and jquery-validation "sees" a blank field because the variable "val" is always set to "". On the other side, element.hasAttribute( "contenteditable" ) correctly returns false on IE11.

Reverting the patch #2142 solves the problem for me, and everything seems to work again like it did in 1.17.0

Please could you have a look at this problem and confirm me that you can reproduce it on an other IE11 installation?
It would be then great to have a 1.18.1 release, because it's a very nasty regression ;)

Thank you!