<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
</body>
<script>
var People = function(){
this.name = "Jackey";
};
People.prototype.getName = function(){
return this.name;
};
var Man = function(){
this.sex = "male";
People.call(this);
};
//缺点 ，name 是父类中的属性，如果修改会影响子类
//Man.prototype = People.prototype;
//new 新开内存
Man.prototype = new People();
Man.prototype.constructor = Man;//可随意修改People的属性，不会影响到Man
var man = new Man();
console.log(man.getName());
</script>
</html>
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
</body>
<script>
var People = function(){
this.name = "Jackey";
};
People.prototype.getName = function(){
return this.name;
};
var Man = function(){
this.sex = "male";
People.call(this);
};
//缺点 ，name 是父类中的属性，如果修改会影响子类
//Man.prototype = People.prototype;
//new 新开内存
Man.prototype = new People();
Man.prototype.constructor = Man;//可随意修改People的属性，不会影响到Man
var man = new Man();
console.log(man.getName());
</script>
</html>
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
</body>
<script>
var People = function(){
this.name = "Jackey";
};
People.prototype.getName = function(){
return this.name;
};
var Man = function(){
this.sex = "male";
People.call(this);
};
//缺点 ，name 是父类中的属性，如果修改会影响子类
//Man.prototype = People.prototype;
//new 新开内存
Man.prototype = new People();
Man.prototype.constructor = Man;//可随意修改People的属性，不会影响到Man
var man = new Man();
console.log(man.getName());
</script>
</html>
javascript 继承 constructor 需要注意点
原文：http://www.cnblogs.com/lihaozhou/p/4060862.html