Evaluating JavaScript Code with 'jrunscript' Interactively

JavaScript Tutorials - Herong's Tutorial Examples

Dr. Herong Yang, Version 2.20

JavaScript Tutorials - Herong's Tutorial Examples

∟'jrunscript' - JavaScript Shell Command from JDK

∟Evaluating JavaScript Code with 'jrunscript' Interactively

This section provides a tutorial example on how to evaluate JavaScript codes with 'jrunscript' in interactive mode. Each line is evaluated as an expression. The value is printed on the screen.

Another way to run JavaScrip code with "jrunscript" is to use "jrunscript" in interactive mode. Several notes about using "jrunscript" interactive mode:

Each line of code will be evaluated immediately as expressions.
Each line of code must be one or multiple complete statements. A single statement can not be entered in multiple lines.
If there are multiple expressions involved in a single line of code, the value of the last expression is printed on the screen at the end of the evaluation.

I did a number of tests with "jrunscript" interactive mode and recorded some of them below:

C:\herong>\progra~1\java\jdk1.6.0_02\bin\jrunscript 

js> println("Hello World!");
Hello World!

js> x = "Apple"; y = "Orange";
Orange

js> println(x + ' and ' + y);
Apple and Orange

js> var s = 0;

js> for ( i=1; i<=100; i++) {
script error: sun.org.mozilla.javascript.internal.EvaluatorException: 
   missing } in compound statement (<STDIN>#1) in <STDIN> at 
   line number 1

js> for ( i=1; i<=100; i++) { s += i; }
5050.0

js> println(s);
5050

js>

Table of Contents

About This JavaScript Tutorial Example Book

Introduction to JavaScript

ECMAScript Language Specification and JavaScript Dialects

Data Types, Variables and Expressions

Flow Control Statements

Creating, Accessing, and Manipulating Arrays

Defining and Calling Functions

Web Browser Supporting JavaScript

Server-Side and Client-Side Web Scripting

Introduction to Objects

Defining Your Own Object Types