The majority of web developers are dependent on jQuery as their go-to JavaScript framework. It is flexible and evolving with every version. The community is also very huge, so you can always find a solution with a Google search.
You’ve likely come across points where jQuery is not an option. This is quite common with content management systems which prioritizes it’s own native JS framework over jQuery.
When in doubt, just code it. You’ll be able to achieve certain things that are usually done with jQuery using this guide. It has both tips and practical examples so you won’t feel lost.