Prototype


该原型属性可以让你的属性和方法添加到任何对象(数字,布尔值,字符串和日期等)。

注 - Prototype是一个全局属性,几乎可用于所有对象。

使用以下语法创建布尔原型。

object.prototype.name = value

以下示例显示如何使用prototype属性向对象添加属性。

<html>

   <head>
      <title>User-defined objects</title>
      <script type = "text/javascript">
         function book(title, author){  
            this.title = title;  
            this.author = author;  
         }  
      </script>
   </head>

   <body>
      <script type = "text/javascript">
         var myBook = new book("Perl", "Tom");  
         book.prototype.price = null;  
         myBook.price = 100;  
         document.write("Book title is : " + myBook.title + "<br>");  
         document.write("Book author is : " + myBook.author + "<br>");  
         document.write("Book price is : " + myBook.price + "<br>");  
      </script>
   </body>

</html>

成功执行上述代码后,将显示以下输出。

Book title is : Perl
Book author is : Tom
Book price is : 100