Gaurav Seth's WebLog : JScript

The AJAX Experience : Presentation and Webcasts

GauravS — Tue, 06 Jan 2009 03:44:00 GMT

Select presentations and webcasts from the The AJAX Experience 2008 conference are now available. View them from here ....(read more)

AJAX Performance Bestpractices

GauravS — Fri, 21 Nov 2008 23:59:00 GMT

Recently someone asked me about the best practices for AJAX performance. Though this information is scattered all around, I thought it might be useful to capture it in a single blog post. So here you go >>> The AJAX performance tips from JScript...(read more)

TAE 2008: Analyzing the AJAX Application Performance

GauravS — Sun, 05 Oct 2008 21:31:00 GMT

It is for the first time that I attended and presented at a web-developer conference. That too, one of the conferences which surely sees amongst the major turnout of JavaScript influentials - “ The AJAX Experience 2008 ”. My talk was around "Analyzing...(read more)

JScript Engine Improvements - IE8 beta.

GauravS — Sat, 08 Mar 2008 23:50:00 GMT

In this post, I just wanted to lay focus on some of the improvements that have been done in the JScript engine shipped as a part of IE 8 Beta release . These improvements include: · Changes to the JScript Garbage Collector to reduce circular memory leaks...(read more)

JScript and IE8 Beta

GauravS — Fri, 07 Mar 2008 00:03:00 GMT

As a follow up my previous post JScript Performance in IE8 Beta , here is another set of reviews that I found about the JScript engine shipped in IE8 beta. · “…SunSpider JavaScript test on Internet Explorer 8. Previously it failed miserably coming in...(read more)

JScript Performance in Internet Explorer 8 Beta

GauravS — Thu, 06 Mar 2008 13:21:00 GMT

The cat’s finally out of the bag. IE 8 Beta is finally live and available publically for download. Here is a link to the blog post JScript in Internet Explorer 8 Beta 1 for Developers detailing the work done by the JScript team. Here are a first few set...(read more)

Classes in Java Script

GauravS — Wed, 07 Nov 2007 22:04:00 GMT

Here is a series of posts on “Classes in JScript” written by Ritesh from the JScript team at MS: Classes in Jscript - Part I Classes in JScript – Part II: Instance Properties / Methods & Class Properties / Methods Classes in JScript – Part III: Class...(read more)

Difference in Java Script behavior across browsers

GauravS — Mon, 05 Nov 2007 23:23:00 GMT

Many a times, Java Script developers are perplexed by the fact that the same piece of Java Script code written by them behaves differently on the different web browsers. The reason for the same is the different implementations of the ECMA Script language...(read more)

JScript COM interop...

GauravS — Tue, 25 Sep 2007 19:27:00 GMT

Here are links to a virtual series written by Sheetal, one of the developers in the JScript team on Jscript COM interop · Interoperability of JScript with COM · Calling functions of COM object from JScript · Script CallBack from COM · Passing Parameter...(read more)

Got JScript Questions - Post them here...

GauravS — Tue, 25 Sep 2007 13:48:00 GMT

One of the things that I did not capture on my Quick JScript References blog was a repository of the online MS community resources where one can post questions specific to JScript . The reason was that we were in the process of establishing a JScript...(read more)

Some Quick JScript References

GauravS — Fri, 07 Sep 2007 12:56:00 GMT

Looking for documentation regarding the different flavors of JScript and not sure which one is correct. While I was adding the documentation pages to my blog, I thought it might be worth to post them at the blog as well as a follow up to my blog regarding...(read more)

Improve AJAX Performance | Download Windows Script 5.7 now

GauravS — Mon, 27 Aug 2007 14:03:00 GMT

Recently, Microsoft made a public release of Windows Script v5.7 which ships with different flavors of Windows® Vista for for Windows® 2000/XP as well as Windows® 2003 Server.

Below are the download links for the same

Download Windows Script 5.7 for Windows XP

Download Windows Script 5.7 for Windows 2003 Server

Download Windows Script 5.7 for Windows 2000

IE and especially AJAX users should surely install this update. Don (who’s the test lead on the JScript team) has enumerated upon the reasons and advantages one would get by installing the update at our JScript team blog here - http://blogs.msdn.com/jscript/archive/2007/08/12/windows-script-5-7-released-for-windows-2000-windows-xp-and-windows-2003-server.aspx

Note: The release notes for the same are now available at http://download.microsoft.com/download/f/f/e/ffea3abf-b55f-4924-b5a5-bde0805ad67c/Windows Script Release Notes.rtf

Microsoft Ajax View tool

GauravS — Mon, 27 Aug 2007 13:49:00 GMT

Recently, MS made a public release of the Ajax view tool and I thought it's surely worth mentioning and spreading the word around.

Overview snippet of the tool …

The goal of the Ajax View project is to improve developer's visibility into and control over their web applications' behaviors on end-user's desktops.

The Ajax View approach is to insert a server-side proxy (or web server plugin) in-between the web server machines and the end-user's browser. This proxy captures the web application's JavaScript code as it is being sent to a browser and rewrites the code to insert extra instrumentation code. The injected instrumentation code runs with the rest of the web application inside the end-user's browser and can capture performance, call graph, application state and user interaction information, providing visibility directly into the last hop of the user's experience ...

Download from

You can find the download and usage information at http://research.microsoft.com/projects/ajaxview/

More information

John’s blog item about Ajax View on the IE team blog has more information regarding the same: http://blogs.msdn.com/ie/archive/2007/08/23/Analyzing-Web-2.0-Applications-with-Ajax-View.aspx

Difference between JScript, JScript.NET and Managed JScript

GauravS — Thu, 16 Aug 2007 16:33:00 GMT

There are three different types of JScript engines that MS currently offers to the users. In this blog I would like to discuss more about the differences between them and would go into the reasoning for three different types sometime later.

JScript (or native JScript)

Read the intro about this in my previous blog here. The native JScript engine relies primarily on Microsoft's ActiveX/COM to provide much of its functionality. The core engine (jscript.dll) is installed as a Windows/IE component on a user machine and resides in “% SystemRoot%\system32” directory.

JScript.NET

JScript .NET is the next generation of an implementation by Microsoft of the ECMA 262 language. Combining the feature set of previous versions of JScript with the best features of class-based languages, JScript .NET includes the best of both worlds. The JScript.NET engine relies primarily on the .NET Framework to provide much of its functionality and runs on the Common Language Runtime.

Differences in JScript .NET when compared to (native) JScript include true compiled code (as it is converted to MSIL format for the CLR), typed and typeless variables, late- and early-binding, classes (with inheritance, function overloading, property accessors, and more), packages, cross-language support, and full access to the .NET Framework.

Being a part of the .NET Framework, JScript .NET’s core engine Microsoft.JScript.dll is installed at “% SystemRoot%\Microsoft.NET\Framework\vX.XXXXX”. The X.XXXXX specifies the .NET Framework version which is installed. Based on the .NET Framework version that is shipped/installed, the language is at times referred to as version 1.0/1.1/2.0 correspondingly. Also, the language at times is versioned based on Visual Studio’s major version it shipped with – like 8.0 for Visual studio 2005 with which .NET Framework 2.0 was shipped. So JScript.NET-2.0 and JScript.NET-8.0 both refer to the same version.

Managed JScript

Managed JScript is the name that is used for the implementation of the ECMA-262 language over the Dynamic Language Runtime to be delivered by Silverlight. It is the latest addition to the JScript family and was released in MIX07.

Unlike JScript .NET which is less dynamic than the original JScript but provides CLS compatibility, Managed JScript is designed on top of the DLR and provides the features needed for scripting scenarios. Implementation over DLR enables Managed JScript code to works well with not only C#, but also with IronPython , IronRuby, VB among other languages. The Managed JScript engine is installed by Silverlight 1.1 at “%ProgramFiles%\Microsoft Silverlight\Microsoft.JScript.Runtime.dll”.

The official release of Managed JScript is planned as a part of Microsoft Silverlight 1.1 (the Alpha Refresh release of the same can be downloaded from here) and next versions of ASP.NET. You can get more information about the same from the official Silverlight website here.

Hope this should get some clarity of the different types of JScript offerings from Microsoft. I would follow up with more on JScript soon.

The World of JScript, JavaScript, ECMAScript …

GauravS — Wed, 15 Aug 2007 10:42:00 GMT

Change is inevitable, except from vending machines – a quote from an unknown source but so true. With the release of the Visual J# 2.0 Redist-SE over, the time has come for me to change and look for bigger and brighter challenges. I recently moved to the JScript team at Microsoft IDC. So yes, that would mean going ahead you would read quite a bit on the same at my blogs. Here is a short summary of a few definitions:

What is JScript?

JScript is Microsoft’s implementation of the ECMAScript scripting language. JScript is implemented as a Windows Script engine, which means it can be "plugged in" to any application that supports Windows Script, such as Internet Explorer, Active Server Pages, and Windows Script Host. JScript was first supported in Internet Explorer browser 3.0 and typical file extension of JScript source code files is .js.

Got you, but then what is ECMAScript?

ECMAScript is a scripting programming language, standardized by Ecma International in the ECMA-262 specification. There are three editions of ECMA-262 published, and the work on the fourth edition is in progress.

ECMAScript is supported in many applications, especially web browsers where it is is often referred to as JavaScript or JScript. The various dialects typically include their own, different standard libraries, of which some are standardized separately – such as the W3C-specified DOM. Some implementations, of the same have a completely different set of libraries. This means that applications written in one dialect of ECMAScript will not likely work in another, unless they are designed to be compatible

What is JavaScript? How is it different from JScript?

"JavaScript" is actually Netscape Communications Corporation's (and now the Mozilla Foundation's) implementation of the ECMAScript standard.

In addition to other internal implementation differences, the existing version of JScript uses non-generational mark-and-sweep garbage collection whereas JavaScript (the original implementation of which is the SpiderMonkey engine) uses a generational mark-and-sweep system.

Note: Though people often use JScript and JavaScript interchangeably, which is because of the fact that these languages are very similar, it is important to note that neither of them is a simplified version of Java as some may think. Other than incomplete syntactic resemblance and the fact that both JScript/JavaScript and Java can provide executable content in web browsers, the two languages are unrelated.

Would follow up with more soon …