Update...
The Silverlight Dynamic Language SDK 0.5.0 Release Notes posted March 23rd, 2009 on CodePlex, contained this little gem:
Managed JScript has been removed from
the package.
When asked in this thread about the future of Managed JScript (IronJScript), Bill (billchi), a coordinator on the Dynamic Language Runtime forum, had the following to say:
The DLR JScript was experimental for
informing the design of the DLR
(expression trees, interop, callsites,
hosting, etc.). The JS we released
with asp futures and the Silverlight
dynamic sdk became very old and
unserviceable as the DLR continued
evolving for release in CLR 4.0.
Unfortunately, there are no plans at
this time to develop and release a
DLR-hostable JScript.
Thanks,
Bill
(edit to add quote from a later post)
The JScript team will continue
supporting using native Jscript
(jscript.dll) with IActiveScript.
They’ll also continue to service
Jscript.NET, but they aren’t making
other commitments at this point.
Bill
Considering the JScript.NET scripting API's are now all obsolete (though they are still present in .NET 2.0), there therefore appears to be no .NET upgrade path off of the ActiveScripting implementation of JScript (JavaScript).
May I suggest that discussion (protest ;-) be directed to that thread.