Now that we are throwing a custom JS object for the core exceptions, and the base work is done, we should be throwing the different objects for the different types of exceptions.
Created attachment 18229 [details] patch This patch makes JS objects for all the Exception types, and uses a shared base class for the implementation. I have tests for the EventException, RangeException, and XPathExceptions, and am still working on making SVG and XHR tests, but I thought I would put this up for review while I figured out how to do that, in order to make sure that I was on the right track with it.
Comment on attachment 18229 [details] patch The approach looks sane. My impression was you were going to add more tests before we did a real review. You also just noted over IRC that the XHR exceptions were different from expected.
Comment on attachment 18229 [details] patch I'm really worried that the named constants that are members of the classes are not the same values as the same-named constants in the JavaScript language binding. Otherwise, I love this. r=me
Landed in r29073.