向基 ECMAScript (JavaScript) Object 对象提供扩展的类似反射的功能。
Object 扩展是 Microsoft AJAX Library 的一部分。这些扩展为内置的 JavaScript Object 对象添加了功能。 Object 扩展提供有关类型化实例的类似反射的信息。使用这些方法可发现对象的类型和类型名称。
Object.getType 函数
返回指定对象实例的类型。
使用 getType 函数可以获取表示对象的运行时类型的新类型实例。
/* param instance：要返回其类型的对象 return：一个类型示例，表示 instance 的运行时对象 */ var typeVar = Object.getType(instance);
Object.getTypeName 函数
返回标识对象的运行时类型名称的字符串。
使用 getTypeName 函数可确定对象的运行时类型名称。类型名称是以字符串的形式返回的，该字符串表示完全限定类型名称。
/* param instance：要为其返回运行时类型名称的对象。 return：一个字符串，标识 instance 的运行时类型名称 */ var typeNameVar = Object.getTypeName(instance);
示例代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title>Samples</title> </head> <body> <form id="form1" runat="server"> <asp:ScriptManager runat="server" ID="ScriptManager1"> </asp:ScriptManager> <script type="text/javascript"> Type.registerNamespace('Samples'); // Define and register a Samples.Rectangle class. Samples.Rectangle = function(width, height) { this._width = width; this._height = height; } Samples.Rectangle.prototype.getWidth = function() { return (this._width === undefined) ? null : this._width; } Samples.Rectangle.prototype.getHeight = function() { return (this._width === undefined) ? null : this._height; } Samples.Rectangle.registerClass('Samples.Rectangle'); // Define and register a Samples.Square class. Samples.Square = function(length) { this._length = length; } Samples.Square.prototype.getLength = function() { return (this._length === undefined) ? null : this._length; } Samples.Square.prototype.setLength = function(length) { this._length = length; } Samples.Square.registerClass('Samples.Square'); // Create instances of Square and Rectangle and discover their types. Samples.testObjectReflection = function() { var width = 200; var height = 100; var a = new Samples.Rectangle(width, height); var length = 50; var b = new Samples.Square(length); var name = Object.getTypeName(a); // Output "The type name of object a is: Samples.Rectangle" alert("The type name of object a is: " + name); var isSquare = Samples.Rectangle.isInstanceOfType(b) // Output "Object b is an instance of type Square: false" alert("Object b is an instance of type Square: " + isSquare); var c = Object.getType(b); name = Object.getTypeName(c); // Output "The type name of object c is: Function" alert("The type name of object c is: " + name); var isSquare = Samples.Square.isInstanceOfType(c); if (isSquare) { var newLength = a.getWidth(); c.setLength(newLength); alert("Object c is a Square with a length of: " + c.getLength()); } } // Run the sample. Samples.testObjectReflection(); </script> </form> </body> </html>