Javascript error on answers.launchpad.net

[Curtis Hovey]

The front page to Answers <http://answers.launchpad.net/> is throwing an error:

_2fe has no properties

https://launchpad.net/+icing/rev117/MochaKit.js
    2880 var _300=(_2fe.getElementsByTagName(_2fc)||self._document.all);

Traceback:
#0: function anonymous(_2fc=string:"*", _2fd=string:"foldable", _2fe=HTMLDocument:{0}) in <https://launchpad.net/+icing/rev117/MochiKit.js> line 2879
#1: function activateFoldables() in <https://launchpad.net/+icing/rev117/launchpad.js> line 226
#3: function anonymous(_3de=Event:{0}) in <https://launchpad.net/+icing/rev117/MochiKit.js> line 3863

There is nothing foldable on the page, so I expect this call to greacefully exit.

[Curtis Hovey (sinzui)]

I have filed a bug with Mochikit: <http://trac.mochikit.com/ticket/255>.

The script dies when the parent element is null in getElementsByTagAndClassName('span', 'foldable', maincontent). I'm adding a test and will exist early if the element is missing.

[Curtis Hovey (sinzui)]

I cannot reproduce this issue in production any more. I have added a sanity check in the code none the less since I was in the code for another reason.

[Curtis Hovey (sinzui)]

I have not been able to reproduce this issue for a whole release now. I'm closing this. This may have been fixed by a cherrypick, or was a by product of a caching problem in my browser.