最简单的继承和多重继承

A继承B和C，但是B和C没有改变

function C(c) {  this.c = c}C.prototype= {  fnc() {console.log(this.c)}}function B(b) {  this.b = b}B.prototype= {  fnb() {console.log(this.b)}}function A(a, b, c) {  B.call(this, b)  C.call(this, c)  this.a = a}A.prototype = {  fna(){console.log(this.a)}}Object.assign(A.prototype, B.prototype, C.prototype)const a = new A(1, 2, 3)console.log(a)const b = new B(2)console.log(b)const c = new C(3)console.log(c)