While attempting to debug a nasty session/cookie problem under FireFox I decided to give V10 a view under Internet Explorer. And immediately ran into a nasty Javascript compatibility problem.

IE's native Javascript debugging capabilities are pretty well non-existent. Fortunately, it's pretty easy to set up:

• Install the Microsoft Script Debugger (you may have to go through the Windows Genuine Advantage process first)
• In IE, do Tools > Internet Options; then under the Browsing section unselect the two Disable Javascript... items (about 4 items down)

Now when you get a Javascript error, it will prompt you to go into the debugger which in my case, brought me immediately to the error. What was the error? In JSON-style mapping datastructures, don't leave trailing commas. It no work.