What is it?
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 it special?
How difficult is it to master?
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.