A scope safe object creation example with a clean prototype manipulation.

ScopeSafe_WithProto_Constuction.js

function Book(isbn, title, author) {
    if (this instanceof Book) {
        this.isbn = isbn;
        this.title = title;
        this.author = author;
    } else {
        return new Book(isbn, title, author);
    }
}

Book.prototype = {
    constructor: Book,

    toString: function () {
        return "[Book: {isbn: " + this.isbn + ", title: " + this.title + ", author: " + this.author + "}]";
    }
};