Log4J is a really nice Library that aims to facilitate outputting debugging information, but also relevant data, in Java applications. It is highly configurable, using both Categories and Class-Based rules, so that developers can narrow down the problems very well when debugging applications.

Basically, you can dynamically ask the webpage to look at a current object's attributes/values or even change the object's attributes/values. As such, running this script on any browser of your choice should show what attributes your particular browser will allow for an object reference you typed in.