What is it?
JScript is the Microsoft implementation of the
Ecmascript scripting programming language specification.
Although JScript came after Javascript - the other major
implementation of Ecmascript - it was the language submitted to the
European Computer Manufacturers Association as the basis of the
Ecma standard.
Both Javascript and JScript are supersets of Ecmascript, with
their own extensions. Both are used in
Ajax (Asynchronous Javascript and XML) development.
Along with Visual Basic Scripting Edition, Jscript uses the
Windows Script infrastructure, and can be embedded into Windows
applications and plugged into
Internet Explorer, Active Server Pages (ASP), and Windows
Script Host.
The various attempts to bridge the gap between Jscript and
Microsoft's .net platform can cause confusion. Jscript.net was
released in 2001 as the future replacement for Jscript, but it is
little used except in ASP.net, and it is barely supported by
Microsoft's development platforms, or by Internet Explorer.
The JScript implementation for the Dynamic Language Runtime is
Managed Jscript, which is set to become far more important with
Silverlight and the next version of ASP.net. Meanwhile, the new
release, Jscript 8, is said to be fully integrated with .net.
Where did it originate?
JScript was released with Internet Explorer 3.0 in 1996.
What's it for?
JScript is used mostly for client-side scripting applications,
which are hosted by the browser. JScript 8.0, the newest version,
is Microsoft's latest attempt to link the lingua franca of web
scripting with the .net platform. The primary role of JScript 8.0,
as Microsoft sees it, is "construction of websites with ASP.net and
customisation of applications for the .net Framework", which seems
an unnecessarily limited remit.
With Jscript 8.0, Microsoft has beefed up the language's
class-based, objected-oriented credentials and access to the Common
Language Runtime and .net Framework, while maintaining its
scripting feel and, Microsoft asserts, full backward-compatibility
with earlier versions.
What makes itspecial?
JScript, having an Ecmascript core that is not proprietary to
Microsoft, can be used freely on non-Microsoft platforms, unlike
the fully proprietary VBScript. From JScript it is just a short hop
to Javascript, with an even wider market for your skills.
How difficult is it to master?
Like Javascript, JScript derives its syntax and other
conventions from Java, and ultimately from C++, meaning those
familiar with Java and C/C++ will find it easy to learn.
What systems does it run on?
To a greater or lesser extent, JScript runs on all browsers,
though different browsers implement the Ecmascript languages
differently. The proprietary extensions will only be recognised by
Internet Explorer.
What's coming up?
Ecmascript Edition 4. JScript 8.0 already incorporates some of
the proposed functionality.
Web and .net developers with Jscript can earn from £20,000 to
£35,000.
Microsoft's
developer network has some useful JScript training resources
and tutorials online.