问题
I'm a little confused about how to use undoManager in Firefox. According to Mozilla, Firefox 20 now has support for it, but I can't figure out where. I've checked under document, Objects, etc., but can't find it anywhere. I'm sure I'm missing something obvious, so can anyone help?
回答1:
You have to set the "dom.undo_manager.enabled" preference to use it, so far, since the spec is still in flux.
来源：https://stackoverflow.com/questions/15888611/undomanager-support-in-firefox