This post inspired me to re-check my app on Safari & IE, and discovered it no longer worked on either. Reason: if you say "thingy.attribute === undefined", and

This post inspired me to re-check my app on Safari & IE, and discovered it no longer worked on either. Reason: if you say "thingy.attribute === undefined", and thingy itself happens to be undefined, then it works on Firefox only. Ooopsie.