I'm trying to understand how to properly use caching in jQuery.

I have a few cases.

Case A:

1. $('.element').fadeIn();
2. $('.element.active').fadeOut();

I'm assigning element to a variable.

How to add class 'active' to this variable?

Case B:

1. $('.element').fadeIn();
2. $('.element > .child').fadeIn();

How to use .find() method to select direct child of the element?

Case C:

1. $('.element').fadeIn();
2. $('.element, .other-element').fadeIn();

How to add other element separated by comas to a variable?