kamens/khan-exercises — comment on commit a7605a3656ee88f07664a4513c5c50e2f4cde5a3
File: khan-exercise.js line 929
By kamens:

Glancing at the jquery code, I believe this is specifically for expando properties on DOM elements, not arbitrary objects. Either way, should run into this in IE testing if it doesn't work. Thx for the heads-up.