What are these mysterious methods of a javascript exception?
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I examined a javascript exception in Google Chrome.

![enter image description here][1]

And I noticed the functions `get message`, `get stack`, `set message`, and `set stack`. I tried catching this exception and running `alert(e.get_message());` only to get an error. I also tried to run `alert(e.get message());`, which obviously returned another error due to the space.

What are these mysterious methods, and how does a developer call them?


  [1]: http://i.stack.imgur.com/jvEPK.png