Yes, we heard you the first time. The code snippet kn0where posted has the same effect. :)
I looked into this some more, and I think the actual difference between `document.documentElement.contentEditable` and `document.designMode` is subtle and probably mostly just in principle: since contentEditable is set on elements, someone with only access DOM access could potentially toggle it. But someone with only DOM access cannot turn `document.designMode` off.
For example, let's say your making mockups and want to change some text. This lets you do that really quickly.