Notes about JScript

JScript and Developer Tools in IE8 Beta 2

As you might be aware that Internet Explorer Beta 2 was released few weeks back. In this JScript team has added new developer features. We have added some great features to the JScript Debugger apart from improving the existing features. The debugger now has syntax colored sources, support for console.log, break on error etc. You can read more about the debugger features in this post on JScript blog.

Along with debugger, Developer Tools now also has a JScript Profiler to help you make your page more optimal. The profiler shows you report in function view and in call tree view. I specially like call tree view as it can help in figuring out the hot path in the application. Sameer has written a detailed blog on the profiler features.

Apart from these Developer Tools feature we have also added native JavaScript Object Notation (JSON) support in the JScript engine. Now you can use a native JSON object to serialize and de-serialize JScript objects. This way is more secure and better performing. Internet Explorer 8 is the first browser to support JSON natively! You can read more about JSON support in this blog by Corneliu.

You should also check out the JScript PM Channel 9 video where our PM team (including me :)) talks about IE8 Beta 2 features.

Using Visual Studio for Managed JScript

If you use Visual Studio for developing your Silverlight apps and wish to start debug session Managed JScript by just pressing F5, Laurence Moroney has posted a blog entry about using Dynamic Languages in Silverlight with Visual Studio. The article shows how you can create a project for DLR languages and start Chiron for debugging.

What's new for JScript developers in IE8

If you have ever struggled to debug a JScript bug in Internet Explorer, you have a new friend – Developer Tools in Internet Explorer 8. With Internet Explorer Beta 1, you get built-in developer tools including a full feature JScript debugger. To know more about it, read my debugger overview post on the JScript blog.

Apart from this we have also fixed the circular memory leak problem in IE8 and we have improved performance of the JScript engine.

Cool Managed JScript app

John Lam has written a nice post on how you can use cross-language integration features provided by Managed JScript to create a sophisticated Silverlight 2 application. He uses Managed JScript for tying together IronPython, C# app and Flicker APIs to create a cool app.

You can also download code for this app from his website.

Managed JScript in Silverlight 2

With Silverlight 2 Beta 1, we have released a refresh for our Dynamic Language Runtime (DLR) based JScript engine code named ‘Managed JScript’. Managed JScript team will have some blog posts to help you take most advantage of the features provided in this JScript engine.  For more posts on Managed JScript and other work we are doing on JScript, please keep checking our JScript team blog.

In Silverlight 2 Beta 1, DLR and languages on top of DLR like Managed JScript are available as part of Silverlight 2 SDK.

For a JScript developer building Silverlight application, Managed JScript is the best JScript/JavaScript engine to use as this frees you from quirks in the JScript implementation of different browsers. With Managed JScript you  won’t need to worry about cross-browser issues and won’t need to test in all browsers. You can code once and run in all browsers.  You also get access to the .NET platform and Silverlight controls which are not accessible in browser JScript. You can take advantage of interoperability between dynamic languages provided by DLR. This lets you use libraries written in other dynamic languages like Python or Ruby.

Managed JScript announced

At MIX07 Microsoft released a new implementation of JavaScript on top of Dynamic Language Runtime (DLR) as part  of Silverlight  1.1 Alpha release. The brand new JavaScript implementation code named “Managed JScript” brings all the power of managed world to JavaScript developers. This release provides cross-language support and access to the .NET Framework along with ECMAScript Edition 3 feature set. We are working to make sure that Managed JScript is a first class language on top of DLR.

Managed JScript is different from JScript.NET. Managed JScript is a brand new implementation based on infrastructure provided by DLR. It is an implementation of ECMAScript Edition 3 with added support for CLR and DLR. Being based on DLR, it nicely interoperates with other dynamic languages. Managed JScript doesn’t support JScript.NET Classes, typed variables and generation of assemblies.

A QuickStart guide for programming Silverlight using Managed JScript and other dynamic languages is available at Silverlight site. There are some cool samples available at http://www.codeplex.com/dynamicsilverlight. You are welcome to add your DLR based samples on CodePlex. Also Jim Hugunin  is now blogging about DLR’s design and other details. Jim Hugunin and John Lam gave a very interesting talk at MIX today showing the power of DLR and Silverlight by gluing together code from different languages and creating a brand new sample.

Managed JScript is also available as part of Microsoft ASP.NET Futures (May 2007) for use as server side dynamic language. A walkthrough on using Managed JScript and other dynamic languages in ASP.NET is available.

For more details of work we are doing on JScript, please keep checking our JScript team blog.