JS prototype inheritance can only inherit instances, not constructors

js The prototype inherits the disadvantages of the constructor

• modify Person The constructor will affect the subclass that inherits it

function Person(){this.sex = 'man'};
function Man(){};
Man.prototype = Person;

var m1 = new Man();
m1.sex;//'man'

//  modify Person The constructor will affect the subclass that inherits it 
delete Person.sex;
m1.sex;//undefined

js Prototypes inherit constructor instances to avoid disadvantages

function Person(){this.sex = 'man'};
function Man(){};
Man.prototype = new Person();
Man.prototype.construct = Man;

var m1 = new Man();
m1.sex;//'man'

//  modify Person The constructor does not affect the subclass that inherits it 
delete Person.sex;
m1.sex;//'man'