If you learn JavaScript properly then you will very quickly have your own library of code that fixes all of those quirks and can just use the ones you need. Plus once you know JavaScript a few seconds more and you will know jQuery as well - saving about 3/8 of the learning time to learn both.
The way many people use jQuery it is like placing your house into your hand luggage to go on a short trip rather than just taking what you need.
Also there are now two versions of JQuery - one that is huge and provides patches for every imaginable IE6 browser quirk - and one that provides the same functionality for modern browsers that is a small fraction of the size and becoming smaller all the time now that most JQuery commands are being adopted into JavaScript itself. The main purpose of JQuery wasn’t to fix the quirks, it was to add commands that the author considered should be in JavaScript and so JQuery itself should disappear within the next few years as what JQuery commands are not in ES6 (due for release in March) will be in ES7. Within 5 years JavaScript will still be around and JQuery will be the history of some of the commands (not implemented using the exact same command but doing the exact same thing).