JavaScript Tutorials - Herong's Tutorial Examples - 2.33, by Herong Yang
The "Function" Object Type - Functions Are Objects
This section provides a quick description and a tutorial example script on the 'Function' built-in object type, which is used to create functions.
The "Function" object type is a special built-in object type to be used to create new functions. It has the following main features:
Here is a tutorial example script showing some of those features:
// Function_Object_Type.js // Copyright (c) 2013 HerongYang.com. All Rights Reserved. // Creating a new function with the "Function()" constructor var sign = new Function("name", "this.signature = name;" + "sign.count++;" ) // Adding an instance property to the function sign.count = 0; // Checking this object println("\nAbout this \"sign\":"); println(" Type = "+(typeof sign)); println(" Instance Of Object: "+(sign instanceof Object)); println(" Instance Of Function: "+(sign instanceof Function)); // Executing it on the current object sign("Herong"); // Calling it on another object var pc = new Object(); sign.call(pc, "IBM"); // Checking the signature println("\nExecution result:"); println(" this.signature = " + this.signature); println(" pc.signature = " + pc.signature); println(" # of calls = " + sign.count);
If you run this script with "jrunscript", you will get:
About this "sign": Type = function Instance Of Object: true Instance Of Function: true Execution result: this.signature = Herong pc.signature = IBM # of calls = 2
Now we know how to create functions with the "Function()" constructor.
Read other "Function" related chapters to see more tutorial examples.
Table of Contents
ECMAScript Language Specification and JavaScript Dialects
Data Types, Variables and Expressions
Creating, Accessing, and Manipulating Arrays
Defining and Calling Functions
Web Browser Supporting JavaScript
Server-Side and Client-Side Web Scripting
Defining Your Own Object Types
Inheritance of Properties and Methods through the Prototype Object Chain
'jrunscript' - JavaScript Shell Command from JDK
Using Functions as "Function" Objects
►Introduction to Built-in Object Types
Overview of Built-in Object Types
The "Object" Object Type - The Root Object Type
The "Global" Object Type - The Invisible Global Container
Global Properties and Functions Defined in ECMAScript
Global Properties and Functions Provided by "jrunscript"
►The "Function" Object Type - Functions Are Objects
The "Array" Object Type - Arrays Are Objects
The "JSON" Object Type - parse() and stringify()
The "String" Object Type - Not Equal to String Primitive Type
The "Boolean" Object Type - Wrapping Boolean Values into Objects
The "Number" Object Type - Not Equal to Number Primitive Type
The "Date" Object Type - Managing Dates and Times
The "RegExp" Object Type - Regular Expression Patterns
The "Error" Object Type - Runtime Exceptions
The "Math" Object Type - The Math Container
W3C's Document Object Model (DOM) Specifications