About this Book
JavaScript
is Netscape's cross-platform, object-based scripting language. This book
is a reference manual for the core JavaScript language.
This
preface contains the following sections:
New
Features in this Release
JavaScript
version 1.5 provides the following new features and enhancements:
-
-
Runtime errors. Runtime errors are now
reported as exceptions.
-
Number formatting enhancements. Number
formatting has been enhanced to include Number.prototype.toExponential,
Number.protoytpe.toFixed
and Number.prototype.toPrecision
methods. See page 127,
page 128, and page 129.
-
Regular expression enhancements:
-
-
Greedy quantifiers —
+,
*,
?
and {} —
can now be followed by a ? to force
them to be non-greedy. See the entry for ? on page 148.
-
Non-capturing parentheses,
(?:x)
can be used instead of capturing parentheses(x). When
non-capturing parentheses are used, matched subexpressions
are not available as back-references. See the entry for
(?:x) on
page 148.
-
Positive and
negative lookahead assertions are supported. Both assert a match
depending on what follows the string being matched. See the
entries for (?=) and
(?!)
on page 148.
-
The m flag has been
added to specify that the regular expression should match over
multiple lines. See page 146.
-
Conditional function declarations.
Functions can now be declared inside an if clause. See
page 221.
-
Function expressions. Functions can now
be declared inside an expression. See page 254.
-
Multiple catch
clauses. Multiple catch clauses in a
try...catch
statement are supported. See page 231.
-
Constants. Readonly, named constants are
supported. This feature is available only in the C implementation of
JavaScript. See page 215.
-
Getters and Setters. JavaScript writers
can now add getters and setters to their objects. This feature is
available only in the C implementation of JavaScript. See Defining
Getters and Setters in Chapter 7 of the Core JavaScript Guide
for information about this feature.
What
You Should Already Know
This book
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.
JavaScript
Versions
Each version
of Navigator supports a different version of JavaScript. To help you
write scripts that are compatible with multiple versions of Navigator,
this manual lists the JavaScript version in which each feature was
implemented.
The
following table lists the JavaScript version supported by different
Navigator versions. Versions of Navigator prior to 2.0 do not support
JavaScript.
Table 1 JavaScript and Navigator
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)
|
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.
Table 2
JavaScript and Netscape Enterprise Server versions
|
Abbreviation
|
Enterpriser Server version
|
|
NES 2.0
|
Netscape Enterprise Server 2.0
|
|
NES 3.0
|
Netscape Enterprise Server 3.0
|
Where to
Find JavaScript Information
The core
JavaScript documentation includes the following books:
-
-
The Core
JavaScript Guide provides information about the core
JavaScript language and its objects.
-
The Core JavaScript Reference (this
book) 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.
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
book uses uniform resource locators (URLs) of the following form:
http://server.domain/path/file.htmll
In
these URLs, server represents the name of the server on
which you run your application, such as research1 or
www;
domain represents your Internet domain name, such as
netscape.com or
uiuc.edu;
path represents the directory structure on the server; and
file.htmll 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
book uses the following font conventions:
-
-
The monospace font
is 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.
Previous
Contents
Index
Next
Copyright ©
2000 Netscape Communications
Corp. All rights reserved.
Last Updated September 28, 2000
|
