Including JavaScript Codes as External Files

JavaScript Tutorials - Herong's Tutorial Examples

∟Including JavaScript Codes as External Files

This section provides a quick description of how to save JavaScript codes into separate files and include them into HTML documents with 'script' tags. A tutorial example is provided on calling a function stored in a separate JavaScript file.

Sometime, if you have a large amount of JavaScript code that needs to be shared by multiple HTML documents, you can store the JavaScript code in a separate file, and use the "script" tag to retrieve this tile.

The syntax of the "script" tag to retrieve a separate JavaScript code looks like this:

<script type="text/javascript" src="JavaScript_file_URL">
</script>

To test this feature, I wrote this JavaScript code and saved as a file, Hello_World_Function.js:

function printHello() {
   document.write('Hello World!');
}

Now I can modify my HTML document in the previous section to retrieve this file with a "script" tag:

<html>
<!-- Hello_World_Head_Include.html
   Copyright (c) 2002 HerongYang.com. All Rights Reserved.
-->
<head>
<title>printHello() Function in an Include File</title>
<script type="text/javascript" src="Hello_World_Function.js">
</script>
</head>
<body>
<pre>
<script type="text/javascript">
   printHello();
</script>
</pre>
</body>
</html>

Of course, the output of the modified JavaScript page will be the same text: "Hello World!".

While testing this "src" attribute of the "script" tag, I also notice that the shorthand form of the empty tag does not work:

<script type="text/javascript" src="JavaScript_file_URL"/>

You must use the close tag </script> explicitly!

Table of Contents

About This 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

JavaScript Support in Web Browsers

Including JavaScript Codes with HTML "script" Tags

type="text/javascript" or language="JavaScript"

JavaScript Version Supported by Browsers

Including 'script' Tags in String Literals

Escaping 'script' Tags in String Literals

Using HTML Entities to Protect HTML Tags

►Including JavaScript Codes as External Files

DOM API - The "document" Object

DOM API - The "window" Object

DOM API - The "window.open" Method

Event Listeners and Objects

'javascript:' Pseudo-URL Addresses

JavaScript Console in Google Chrome

JavaScript Console in Mozilla Firefox

JavaScript Console in Apple Safari

JavaScript Console in IE (Internet Explorer)

Server-Side and Client-Side Web Scripting

Introduction to Objects

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

AJAX (Asynchronous JavaScript And XML)

References

Full Version in PDF/EPUB