详解JavaScript继承方式（三）

/**
 * @param {Function} subCls
 * @param {Function} superCls
 */
function extend(subCls,superCls) {
subCls.prototype = new superCls();
}

/**
 *  父类Person
 */
function Person(){}
Person.prototype.nationality = 'China';
Person.prototype.getNationality = function() {return this.nationality;}
Person.prototype.setNationality = function(n) { this.nationality = n;}

function Man() {}
extend(Man,Person);

Man.prototype.name = 'jack';
Man.prototype.getName = function() { return this.name;}
Man.prototype.setName = function(n) { this.name=n;}

var m = new Man();
console.log(m);
console.log(m instanceof Person);

/**
 * @param {Function} subCls 子类
 * @param {Function} superCls 父类
 */
function extend(subCls,superCls) {
//暂存子类原型
var sbp = subCls.prototype;
//重写子类原型--原型继承
subCls.prototype = new superCls();
//重写后一定要将constructor指回subCls
subCls.prototype.constructor = subCls;
//还原子类原型
for(var atr in sbp) {
subCls.prototype[atr] = sbp[atr];
}
//暂存父类
subCls.supr = superCls;
}

/**
 *  父类Person
 */
function Person(nationality){
this.nationality = nationality;
}
Person.prototype.getNationality = function() {return this.nationality;}
Person.prototype.setNationality = function(n) { this.nationality = n;}
/**
 *  子类Man
 */
function Man(nationality,name) {
Man.supr.call(this,nationality); //很重要的一句，调用父类构造器
this.name = name;
}
Man.prototype.getName = function() {return this.name;}
Man.prototype.setName = function(n) {this.name=n;}

extend(Man,Person);
var m = new Man('USA','jack');
console.log(m)
;m.setName('lily');
console.log(m.name);