JavaScript Tutorials - Herong's Tutorial Examples - 2.33, by Herong Yang
Conditional "if" Statement Examples
This section provides a JavaScript tutorial example showing different types of 'if' statements.
To help you understand how "if" statements work, I wrote the following the JavaScript tutorial example, If_Statements.html:
<html> <!-- If_Statements.html Copyright (c) 2002 HerongYang.com. All Rights Reserved. --> <head><title>If Statements</title></head> <body> <pre> <script type="text/javascript"> // Single-statement "if" document.write('\n'); var is_january = true; if (is_january) document.write("Happy New Year!\n"); // Multi-statement "if" document.write('\n'); var is_log_on = true; if (is_log_on) { document.write("Open the log file.\n"); document.write("Write the log message.\n"); document.write("Close the log file.\n"); } // "if ... else" statement document.write('\n'); var is_admin = false; if (is_admin) { document.write("Display the delete button.\n"); document.write("Display the edit button.\n"); } else { document.write("Display the view button.\n"); } // "if ... else if" statement document.write('\n'); var week_day = 4; var open_hours; if (week_day == 0) { open_hours = "closed"; } else if (week_day >= 1 && week_day <= 5) { open_hours = "open from 9:00am to 9:00pm"; } else if (week_day == 6) { open_hours = "open from 9:00am to 5:00pm"; } else { open_hours = "undefined"; } document.write("The library is " + open_hours + ".\n"); </script> </pre> </body> </html>
The output of this sample JavaScript is:
Happy New Year! Open the log file. Write the log message. Close the log file. Display the view button. The library is open from 9:00am to 9:00pm.
Table of Contents
ECMAScript Language Specification and JavaScript Dialects
Data Types, Variables and Expressions
►Conditional "if" Statement Examples
"switch ... case" Statement Example
"while" Loop Statement Example
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
W3C's Document Object Model (DOM) Specifications