Why does the console say error in js?

Question

CMS

I use swiper slider as a slider, as well as fancybox for galleries.
Neither one nor the other works.
About the slider, the console "says" an error, they say

TypeError: $(...)[actionDom] is not a function

And the same goes for fancybox

TypeError: $(...).fancybox is not a function

Please turn your nose in the right direction.
At the same time, everything works locally.
UPD. Really it is necessary to push scripts in header?

Answer 1

Scripts can be pushed anywhere, the main thing is that you do not try to call them before they are loaded.

$( document ).ready(function() {
   ...
});