To test Javascript in Firefox, I use the Javascript Shell or Javascript Environment extensions. To debug, I use the "Venkman" extension. And to walk the DOM, I use the DOM Inspector.

What similar tools exist for Internet Explorer?

Could you repeat the question in English, please?

Microsoft do a tool, and I'm damned if I can remember what it is called.

Arghhhhh!

OK - I remember now.

Fiddler is a HTTP Debugging Proxy which logs all HTTP traffic between your computer and the Internet. Fiddler allows you to inspect all HTTP Traffic, set breakpoints, and "fiddle" with incoming or outgoing data. Fiddler is designed to be much simpler than using NetMon or Achilles, and includes a simple but powerful JScript.NET event-based scripting subsystem.

Is that the sort of thing you need?

Nope (but thanks for the legwork). I want something that runs javascript fragments in IE, so's I can see if they work liek they do in Firefox.