Core JavaScript 1.5 Guide:About
From MDC
Contents |
[edit] New features in JavaScript versions
[edit] What you should already know
This guide assumes you have the following basic background:
- A general understanding of the Internet and the World Wide Web (WWW).
- Good working knowledge of HyperText Markup Language (HTML).
Some programming experience with a language such as C or Visual Basic is useful, but not required.
[edit] JavaScript versions
| JavaScript version | Navigator version |
|---|---|
| JavaScript 1.0 | Navigator 2.0 |
| JavaScript 1.1 | Navigator 3.0 |
| JavaScript 1.2 | Navigator 4.0-4.05 |
| JavaScript 1.3 | Navigator 4.06-4.7x |
| JavaScript 1.4 | |
| JavaScript 1.5 | Navigator 6.0 Mozilla (open source browser) |
| JavaScript 1.6 | Firefox 1.5, other Mozilla 1.8-based products |
| JavaScript 1.7 | Firefox 2, other Mozilla 1.8.1-based products |
| JavaScript 1.8 | Firefox 3, other Gecko 1.9-based products |
Table 1: JavaScript and Navigator versions
Each version of the Netscape Enterprise Server also supports a different version of JavaScript. To help you write scripts that are compatible with multiple versions of the Enterprise Server, this manual uses an abbreviation to indicate the server version in which each feature was implemented.
| Abbreviation | Enterprise Server version |
|---|---|
| NES 2.0 | Netscape Enterprise Server 2.0 |
| NES 3.0 | Netscape Enterprise Server 3.0 |
Table 2: Abbreviations of Netscape Enterprise Server versions
[edit] Where to find JavaScript information
The core JavaScript documentation includes the following books:
- The Core JavaScript Guide (this guide) provides information about the core JavaScript language and its objects.
- The Core JavaScript Reference provides reference material for the core JavaScript language.
If you are new to JavaScript, start with the Core JavaScript Guide. Once you have a firm grasp of the fundamentals, you can use the Core JavaScript Reference to get more details on individual objects and statements.
[edit] Tips for learning JavaScript
Getting started with JavaScript is easy: all you need is a modern Web browser. This guide includes some JavaScript features which are only currently available in the latest versions of Firefox (and other Gecko powered browsers), so using the most recent version of Firefox is recommended.
[edit] An interactive interpreter
An interactive JavaScript prompt is an invaluable aid to learning the language, as it enables you to try things out interactively without having to save a file and refresh a page. The Firefox Error Console, accessible through the Tools menu, provides a simple way to try interactive JavaScript: Just enter a line of code and click the "Evaluate" button.
[edit] Firebug
A more advanced interactive prompt is available using Firebug, a third party Firefox extension. Firebug also provides an advanced DOM inspector, a JavaScript debugger, a profiling tool and various other utilities:
One of the most useful facilities provided by Firebug is console.log(), a function that prints its arguments to the Firebug console. Unlike other programming languages, JavaScript does not have a concept of printing to standard output. console.log() provides a useful alternative, making it much easier to see what your program is doing.
Many of the examples in this guide use alert() to show messages as they execute. If you have Firebug installed you can use console.log() in place of alert() when running these examples.
[edit] Document conventions
JavaScript applications run on many operating systems; the information in this book applies to all versions. File and directory paths are given in Windows format (with backslashes separating directory names). For Unix versions, the directory paths are the same, except that you use slashes instead of backslashes to separate directories.
This guide uses uniform resource locators (URLs) of the following form:
http://server.domain/path/file.html
In these URLs, "server" represents the name of the server on which you run your application (e.g., research1, www), "domain" represents your Internet domain name (e.g., netscape.com, uiuc.edu), "path" represents the directory structure on the server, and "file.html" represents an individual file name. In general, items in italics in URLs are placeholders and items in normal monospace font are literals. If your server has Secure Sockets Layer (SSL) enabled, you would use https instead of http in the URL.
This guide uses the following font conventions:
- The
monospace fontis used for sample code and code listings, API and language elements (such as method names and property names), file names, path names, directory names, HTML tags, and any text that must be typed on the screen. (Monospace italic font is used for placeholders embedded in code.) - Italic type is used for book titles, emphasis, variables and placeholders, and words used in the literal sense.
- Boldface type is used for glossary terms.