class?A?{
????constructor()?{
??????this.x?=?1;
??????this.print=()=>{
??????????console.log(this.x+'A?instance');
??????}
????}
????static?x=2
????static?print()?{
????????console.log(this.x+'A?static');
????}
????print()?{
????????console.log(this.x+'A?prototype');
????}
??}
??A.prototype.x=3;
??class?B?extends?A?{
????constructor()?{
??????super();
??????this.x?=?9;
??????//super.x?=?10;
??????this.m=()=>{super.print()};
??????//console.log(super.x);?//?undefined
??????//console.log(this.x);?//?3
????}
????static?x=20
????static?m()?{
????????super.print();
????}
????m()?{
????????super.print();
??????}
??}
??B.prototype.x=30;
??let?b?=?new?B();
??b.m();
??B.m();
??B.prototype.m();
prototype就是用来溯源的；this看引用的对象；两者应分开查找。
