It's not just about performance. That can be important for complex projects, such as image editors, but it's not why I personally prefer plain JS over jQuery.
However, ask yourself: What's your advantage of using jQuery today? Modern JS is pretty cross browser safe and syntax is becoming simpler and simpler. Modern browsers, like Chrome or FF, have already DOM4 implemented. With that, a lot of jQuery-like methods were accepted: .prepend(), .closest() ... querySelectorAll() is essetially the same es $(...) in jQuery.
Personally, I was surprised how easy and effective it is to write vanilla JS. Which is why the idea of plainJS.com came up. And as a proof of concept, plainJS is naturally fully implemented in plain JS :D And it wasn't hard, and it works properly down to IE 8.
However, ask yourself: What's your advantage of using jQuery today? Modern JS is pretty cross browser safe and syntax is becoming simpler and simpler. Modern browsers, like Chrome or FF, have already DOM4 implemented. With that, a lot of jQuery-like methods were accepted: .prepend(), .closest() ... querySelectorAll() is essetially the same es $(...) in jQuery.
Personally, I was surprised how easy and effective it is to write vanilla JS. Which is why the idea of plainJS.com came up. And as a proof of concept, plainJS is naturally fully implemented in plain JS :D And it wasn't hard, and it works properly down to IE 8.