js物件導向編程，一個具有各種方法，欄位 完整的類

var Book = (function() {    // 私人靜態成員變數  var numOfBooks = 0;  // 私人靜態成員方法  function checkIsbn(isbn) {    ...   }      // Return the constructor.  return function(newIsbn, newTitle, newAuthor) { // implements Publication    // 私人成員變數    var isbn, title, author;    // 私人方法    this.getIsbn = function() {      return isbn;    };    this.setIsbn = function(newIsbn) {      if(!checkIsbn(newIsbn)) throw new Error('Book: Invalid ISBN.');      isbn = newIsbn;    };    this.getTitle = function() {      return title;    };    this.setTitle = function(newTitle) {      title = newTitle || 'No title specified';    };    this.getAuthor = function() {      return author;    };    this.setAuthor = function(newAuthor) {      author = newAuthor || 'No author specified';    };    // Constructor code.    numOfBooks++; // Keep track of how many Books have been instantiated                  // with the private static attribute.    if(numOfBooks > 50) throw new Error('Book: Only 50 instances of Book can be '        + 'created.');    this.setIsbn(newIsbn);    this.setTitle(newTitle);    this.setAuthor(newAuthor);  }})();// 共有靜態方法Book.convertToTitleCase = function(inputString) {  ...};// 共有方法Book.prototype = {  display: function() {    ...  }};