1, js

2. Background language (overload)

3. Overloading in JS (what to do depending on the parameters passed)

4. Js inheritance (prototype inheritance)

(1) Purpose of inheritance

(2) Define two classes

(3) After inheritance

(4) Drawing and understanding

(5) Prototype inheritance

(6) Rewrite

5, call inheritance

Features:

6. Parasitic combination inheritance

Class inheritance in ES6