Will the IE10 Chakra JScript engine available as stand alone accessible from C#?

Microsoft may (actually I think it will) in the future release the IE10 Chakra (JScript engine) as a stand alone module, like google V8 JavaScript Engine.

  • The question is: will the engine accessible from C# like IronPython is?



C# and IronPython are both .NET languages. They share the same run-time, so they can interact easily. There's nothing to suggest that Chakra is built on .NET; rather, given that it compiles the JavaScript to machine code for the sake of performance, I'd say that it won't integrate in the same way.

They might provide a .NET API that would make it possible to pass JS from a .NET language to the JavaScript engine, but that's just conjecture on my part.


The Chakra engine for Javascript is available to C# programs, through the IActiveScript interface. This is not the same as the IronPython model - JS invoked this way through Chakra is not compiled to MSIL, is not .NET logic. It does not run on the CLR/DLR. It runs in its own engine.

// Initialize Chakra (requires IE9 to be installed)
var guid = new System.Guid("{16d51579-a30b-4c8b-a276-0ff4dc41e755}");
Type t = Type.GetTypeFromCLSID(guid, true);
// you must have a p/invoke defn for IActiveScript
var engine = Activator.CreateInstance(t) as IActiveScript;

var site = new ScriptSite(); // this is a custom class

var parse32 = engine as IActiveScriptParse32;

// parse a script
parse32.ParseScriptText(scriptText, null, null, null, IntPtr.Zero, 0, flags, out result, out exceptionInfo);

IntPtr comObject;
engine.GetScriptDispatch(null, out comObject);

// iDispatch is a COM IDispatch  that you can use to invoke script functions. 
var iDispatch = Marshal.GetObjectForIUnknown(comObject);

iDispatch.GetType().InvokeMember(methodName, BindingFlags.InvokeMethod, null, iDispatch, arguments);

Here's a winforms test app written in C# that runs Chakra through this interface:

enter image description here

You can download it from here. (look for the ScriptHost.zip file)

more information:
What is the ProgId or CLSID for IE9's Javascript engine (code-named "Chakra")


The Chakra runtime is now available to call from C# through pinvoke directly. You don't need to go through active script. The api is quite nice and very fast. Here is an example of how to do it on MSDN:



JavaScript (as JScript) is one of the original languages supported by .Net. Support was created before dynamics was available, so in that sence it is different from IronPython... If you need a JavaScript engine in .Net it may be enough for your needs - http://msdn.microsoft.com/en-us/library/72bd815a(v=VS.100).aspx.


Check out what Microsoft just released regarding this topic:


Inside the blog answers you can find the latest comment from Microsoft. The answer is: "Re:Windows scripting – Windows Scripting host supports JavaScript but is not based on Chakra engine. For now, this project does not intend to change the same."


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