function Human(name, age, sex) {
    this.name = name;
    this.age = age;
    this.sex = sex;
    this.speak = function() {
        return "My name is " + this.name + ". I'm " + this.age + " years old, and I can speak";
    }
    this.walk = function() {
        return "This.name " + "can walk";
    }
    }
    //создание  экземляра Human
    var tom = new Human('Tom', 25, 'male');
    //вызов метода toString на объекте tom
    tom.toString() // "[object Object]"
    //переопределие метода toString на Human
    Human.prototype.toString = function(){
        return this.name + " is " + this.age + " years old."
    }
    tom.toString() // "Tom is 25 years old.