The magazine of the Melbourne PC User Group
Learning JavaScript
- for the bookshelf
Major Keary |
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JavaScript is an interpreted programming language, which means it requires
software that processes instructions on-the-fly. The interpreter is built into
Web browser software, so you don't have to install it. The attraction of
JavaScript is that you can learn just enough to satisfy your needs it is not
necessary to learn the whole thing from A to Z.
Unrelated to Sun's Java programming language, JavaScript was introduced by
Netscape in 1995, initially under the name LiveScript. Microsoft later released
its own version, JScript, that was not quite the same. In order to resolve
"compatibility issues Netscape submitted the JavaScript specification to the
European Computer Manufacturers Association (ECMA) ... in 1996 ... [seeking to
have it reissued] as a standardised work" [Powers: Learning JavaScript]. In 1997
the ECMAScript specification was released as ECMA262, of which version 3 is
identical with JavaScript 1.5 and JScript 5.6. There have since been further
developments: JavaScript 1.7 is implemented in FireFox 2; and ECMA-357 (2004)
includes an extension, E4X, that includes native XML.
For a while it looked as if JavaScript was going out of fashion, but it has
become a key element of new Web technologies especially Ajax that have
created a resurgence of interest and new developments. The changes from version
to version and between different vendors don't seem to present many problems;
older versions are still in use depending on the browser. Any difficulties,
according to Shelley Powers (LearningJavaScript) are more likely to be caused by
"differences in the underlying Document Object Model (DOM)", which is unlikely
to present any problems for ordinary users. Those who have used pre-Ajax
JavaScript will find there have been some changes, as the author of
LearningJavaScript observes:
" ... Ajax developers have created libraries to make the language look more like
Ruby or Python or even Java. However, they've also added all sorts of odd
semantics into Ajax applications, with little or no documentation, and obscure
references to items such as 'function closures, and so on. ... So the you have
JavaScript books and libraries that are focussed on the old styles of Web page
development, and new Ajax libraries and books on the new style ... ".
Shelley Powers describes JavaScript as two languages in one: the first is a
fast, friendly, easy-to-use scripting language built into Web browsers and other
applications, offering a range of functions; "the second is a mature,
full-featured, carefully constrained, object-based language, which does require
more in-depth understanding". That is why there is a wide range of JavaScript
texts; one does not have to embrace Ajax or other new Web technologies to use
or just understand JavaScript. If you want to learn JavaScript for use at the
simple level there are some very good resources for beginners, both in print and
on the Web.
JavaScript in Easy Steps
Computer Step publishes books designed to take novices through a topic in easy
steps. At first glance they may appear to be graphics-based (big on pictures and
short on words), but in these titles the generous use of screen shots is there
to illustrate the end result of detailed and annotated code examples.
In this instance the topic is JavaScript. The present (third) edition of JavaScript in Easy Steps includes descriptions of Ajax and DOM. Ajax is a method
of using existing technologies to create Rich Internet Applications (RIA) that
behave in much the same way as a desktop application. The Document Object Model
(DOM) is now a W3C standard observed by most (if not all) browser vendors, which
makes JavaScript even more useful.
This book is not a hand-holding presentation, but as its title says takes
the reader through client-side JavaScript in easy steps. Like all programming
languages, JavaScript has its keywords, syntax, variables, data types,
functions, and so on. The author makes each element the topic of a separate
discussion that is contained in either a single page or a two-page spread. In
each instance example code is used to illustrate the text. It is thorough and
comprehensive, and the style is straightforward. Readers are assumed to be
computer literate and to have a working knowledge of HTML.
JavaScript in Easy Steps is a plain language tutorial that doesn't engage in
jolly banter or humorous asides. If you want to use, and understand, JavaScript
JavaScript in Easy Steps is highly recommended. If not available at your usual
book shop it can be obtained from the Australian distributor at
http://www.woodslane.com.au.
Mike McGrath: JavaScript in Easy Steps 3/e
ISBN 978-1-84078-315-5
Published by Computer Step,
192 pp.,
RRP $29.99 incl. GST |
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Foundation Web Design
This title is published by friends of ED, an imprint of Apress.
Foundation Web Design is a tutorial on Web design and has been included with
JavaScript titles because it places JavaScript in the big picture of Web design.
Designing and creating Web pages is becoming more complex, which makes it
difficult to find texts that suit the needs of users who don't need the latest
technologies. It also provides lucid discussions that explain how and why things
work, the kind of knowledge that some texts expect readers to bring to the
table.
A case study is used throughout to illustrate the design of a professional Web
site. Example code and useful illustrations support the text. JavaScript is one
topic, but it is placed in the context of the other tools (HTML and CSS)
necessary to advanced Web design.
The focus is on essential skills and step-by-step instructions. An excellent
starting point for Web novices who want to learn how to create a Web site from
scratch. Don't be put off by the publication date (2003); for novices and
intermediate-level users that is an advantage because it does not introduce
unnecessary complexities. Foundation Web Design will lay a solid
foundation for those who want to advance their skills.
If your bookshop doesn't have Foundation Web Design in stock it can be obtained
from the Australian distributor, Woodslane, at
http://www.woodslane.com.au.
Sham Bhangai and Tomasz Janowski:
Foundation Web Design
ISBN 1-59059-152-6
Published by Apress,
423pp,
RRP $55.00 incl. GST |
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Modern Web Design with JavaScript and DOM
From the impressive stable of SitePoint, DHTML Utopia: Modern Web Design
Using JavaScript & DOM has been written for "people who have built Web sites
before" and who have experience working with HTML and CSS. Even though it has
been in print for eighteen months which can be a long time in computer
literature the book is still a highly relevant and useful JavaScript resource.
In particular, there is an excellent explanation of the Document Object Model
(DOM), a term that crops up a lot in Web technology literature.
If a Web page offers, or requires nontrivial user input it needs DHTML (Dynamic
HTML), which is "a combination of proper HTML for your content, Cascading
Style Sheets for your design, and JavaScript for interactivity". 'Proper HTML'
means valid HTML: it complies with the rules for how HTML should be written and
which specify that tags should be properly nested (no cross-overs); container
tags should be closed; and a Document Type is mandatory.
The DOM "provides access to the structure of an HTML page by mapping the
elements in that page to a tree of nodes". If you want to use DHTML it is
necessary to understand DOM. Modern Web Design contains a very clear
explanation of what it is and how it is used. In the book an example shows how
DOM is used to build a form that grows as the user fills it in.
Sounds complex? It doesn't have to be. The author walks his readers through all
aspects of building a dynamic Web site using JavaScript and DOM. The content is
presented in tutorial format, but is not confined to bare-bones instruction. The
text is supported by extensive use of annotated example code that can be
downloaded from a companion Web site. The annotation are not terse, and include
lucid explanations of why something is done and how the code works. Topics
covered extend to advanced concepts (such as multilevel drop down menus), remote
scripting, and communicating with the server.
An instance of the book's thoroughness is a discussion of detecting browser
features rather than simple `browser sniffing'. The modern technique is to test
for the necessary features such as DOM compliance rather than identify the
`make' of browser. A dynamic Web site can be built to cope with browsers that
lack a full complement of preferred features.
This book has an extraordinary depth of detail, but maintains a focus on
practical issues and is written in a style that won't leave the reader
floundering. It is not for novices, but anyone with a reasonable understanding
of building Web sites should be able to follow the tutorial without difficulty.
SitePoint doesn't release many books, but those it does publish are of
remarkable quality.
Stuart Langridge:
DHTML Utopia: Modern Web Design Using JavaScript & DOM
ISBN 0-9579218-9-6
Published by SitePoint,
318 pp.,
RRP $74.95 incl. GST |
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Learning JavaScript
This title is more comprehensive than, those mentioned above and has been
prompted by the new prominence of JavaScript as a key part of Ajax. Readers are
not expected to have programming experience, but are expected to be familiar
with HTML/ XHTML and CSS, and have a grasp of how Web applications work. The
book serves as a bridge between the old-style and new-style JavaScript and is
especially useful for "those learning JavaScript because they want to jump into
Ajax".
Even though the book's primary audience is Web designers and programmers,
anybody "who wants, or needs, to integrate JavaScript into [a] personal Web site
or sites ... [or] who uses a content-management tool, such as a weblogging tool,
and wants to better understand the scripting components ... " will find this a
comprehensive and detailed introduction. It is not a learning tool for novices,
who should begin with JavaScript in Easy Steps.
For those who are serious about learning JavaScript there are questions set at
the end of each chapter answers at the back of the book. Extensive use is made
of example code (available for download from a companion Web site) to illustrate
the text; code examples are extensively annotated.
Throughout the book there are valuable asides that include tips, suggestions,
and general notes amongst which are best practice recommendations such
as: Take advantage of short-circuit evaluation by placing the key expression
or less resource-intensive expression first when using logical AND/OR operators.
There are also boxed items that introduce other programs/tools, such as
phpFormGenerator, Eclipse, and free JavaScript editors for Windows,
and JavaScript compression/obfuscator utilities. In addition to that collection
of information there is a chapter that describes a selection of free libraries
and frameworks (with URLs).
Learning JavaScript does not pretend to be a definitive guide; however,
it is remarkably comprehensive and provides discussions of topics that are not
found at least in any useful detail in most other general JavaScript texts.
Security, cookies, and cross-site scripting (XSS) attacks are some of those
topics.
Anyone approaching JavaScript with intention to learn, or extend their
knowledge, should have this title. Good value.
Shelley Powers: Learning JavaScript
ISBN 978-0-596-52746-4
Published by O'Reilly,
335 pp.,
RRP $55.00 incl. GST |
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JavaScript: The Definitive Guide
JavaScript: The Definitive Guide has been a pre-eminent JavaScript
resource since it was first released in 1996 and is now in its fifth edition.
Since the last edition (2002) there have been significant changes in the
JavaScript landscape, as the author notes: "Google released their Gmail
application and people noticed that it didn't behave like the Web sites they
were used to. And Jesse James Garrett published his seminal essay on this new
style of Web development, which he christened Ajax. All of a sudden, the world
of JavaScript had changed". It is now being used to write "programs that are an
order of magnitude longer than the scripts that most of us were writing five
years ago". JavaScript is being used in a much more complex way by developers,
and is an integral part of advanced technologies such as Ajax. There are two
faces to JavaScript: client-side and server-side; most texts are confined to
client-side, but this title covers both.
In spite of those developments JavaScript can still be used at a simple level;
ordinary users don't have to make a choice between what they have been doing
the simple life and the complexities of 'modern' JavaScript. Developers and
professional Web designers need JavaScript in its new role, and JavaScript:
The Definitive Guide has been updated for that audience.
Of course, if you are a user of simple JavaScript who wants to get up to speed
with the latest developments this is the perfect companion to Shelley Powers'
Learning JavaScript.
An example of what can be done, and which is discussed in JavaScript: The
Definitive Guide, is scripting Java (the programming language). It is
possible to embed a Java Script interpreter within a Java application and have
JavaScript, running within that application, script Java
objects. That, of course, is a topic of interest to Java programmers, but it
indicates the way in which JavaScript has been extended.
The book has been divided into parts so as to separate core JavaScript material
from client-side JavaScript, thus making it more convenient for programmers
working in other than a Web browser an environment. In order to fit all the
material in even as large a book as this, the reference entries are terse. For
programmers the principal audience who know JavaScript, but who need a
reference, that terseness is an advantage: information is specific, easy to
find, and is not burdened with superfluous verbiage. In the explanatory sections
the language is clear and the style concise, but eminently readable. Extensive
use of example code supports the text; the code and any errata discovered
after publication is available for download from a Web site.
David Flanagan: JavaScript: The Definitive Reference 5/e
ISBN 978-0-596-10199-2
Published by O'Reilly,
994 pp.,
RRP $85.00 incl. GST |
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Reprinted from the Jan / Feb 2007 issue of PC Update, the magazine of Melbourne PC User Group, Australia
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