Div-element editor?

You just need to add some code.
Editing a div can lead to problems (mainly with IE, that will distort the original content or if you are using any script inside that content), so there are many times where it isn't practical.

Look at the API and the samples, you can generate dinamically an instance and set it's content to be the innerHTML of your div.

sample 08 shows how to use the api, and in general all the samples are useful to understand the behavior.