Apparently we opt the console into JS version 1.8, giving it access to extra JS features that are not available to page scripts today. The console should exactly match the features available to page scripts to reduce confusion. So, for web content at least, we should go back down to the default version. For the browser console, it's fine to stay where we are.

Bug 932513 has more discussion on this topic.

Do we have a larger effort to stop the versioning madness? Experimental JS features should be behind a single "experimental" flag, not versioned.

Ok, I should have followed the "blocks" link... ^_^

Jim, as best I can tell, the web console basically just pipes strings into the Debugger API's evalWithBindings. So, we aren't explicitly saying "eval as you would in JS version 1.8" that I can see. Is there some way we can get the Debugger API to eval with the same JS version a page's script would use?

Wow, it totally should do that. Bug 971673 would fix this, but is stalled waiting for me.

Bug 1390106 fixed this.