As developers of scripts for Acrobat and Reader know, the JavaScript console in Reader is a very handy tool. You can use it to execute your code directly from within the application, and it displays any errors that occur while you run it.
Unfortunately, in Reader the console is very limited. You can't enter or execute code in it. In fact, you can't even display it at will (Ctrl+J doesn't work like in Acrobat).
Well, I've developed a tool that enhances and extends the JavaScript Console in Reader, allowing you to run code, and it even displays any error messages, if any, in the original console.
It also comes with a menu item to display the console window.

The enhanced console (with valid code):

(the code can be copied into the console, and pasted from it)

Result of running the code:

The enhanced console (with invalid code):

Result of running the code:

‍