JavaScript Tutorials - Herong's Tutorial Examples - 2.33, by Herong Yang
The "String" Object Type - Not Equal to String Primitive Type
This section provides a quick description and a tutorial example script on the 'String' built-in object type, which is used to create 'String' objects. Watch out: 'String' objects are not string values.
The "String" object type is a special built-in object type to be used to create a "String" object, which is different than a string value of the string primitive type. It has the following main features:
Here is a tutorial example script showing some of those features:
// String_Object_Type.js // Copyright (c) 2013 HerongYang.com. All Rights Reserved. // Creating a new String object var message = new String("Hello World!"); // Checking this object println("\nAbout this \"message\":"); println(" Type = "+(typeof message)); println(" Instance Of Object: "+(message instanceof Object)); println(" Instance Of String: "+(message instanceof String)); // Using String's inherited property and method var upperMessage = message.toUpperCase(); var l = message.length; var subMessage = message.substring(0,l-7); println("\nExecution result:"); println(" typeof message = "+(typeof message)); println(" message.toString() = "+message.toString()); println(" typeof upperMessage = "+(typeof upperMessage)); println(" upperMessage = "+upperMessage); println(" typeof subMessage = "+(typeof subMessage)); println(" subMessage = "+subMessage); println("\nConverting to String objects on the fly:"); println(" \"...\".length = "+("Hello World!".length)); println(" \"...\".toUpperCase() = " +("Hello World!".toUpperCase()));
If you run this script with "jrunscript", you will get:
About this "message": Type = object Instance Of Object: true Instance Of String: true Execution result: typeof message = object message.toString() = Hello World! typeof upperMessage = string upperMessage = HELLO WORLD! typeof subMessage = string subMessage = Hello Converting to String objects on the fly: "...".length = 12 "...".toUpperCase() = HELLO WORLD!
Now we know how to create "String" objects with the "String()" constructor.
Read other "String" 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