Hi Christopher,
Your general idea is correct, you would use the 'do <script> as <language>' construct to execute a script in another language than Revolution.
But first you have to make sure that Javascript is supported on your platform. You can check the global property 'the alternateLanguages':
On MacOSX, you'll get a list of the OSA-compatible languages that were installed - OSA stands for Open Scripting Architecture, and is the underlying mechanism which allows you to automate tasks using AppleScript and other OSA-compatible languages.
On Windows, Revolution 2.9 will add support for the Windows Script Host system - a system similar to OSA, which allows scripters to automate COM-enabled applications and libraries.
On this Windows XP machine, among other languages, such as VBScript, I get "JScript" - which is the Microsoft implemenatation of ECMAScript, the official name for Javascript.
In short, there's no built-in Javascript, but you can use OSA/WSH to execute scripts in alternate languages, provided they are installed.
Hope this helped,
Jan Schenkel.