That's just a sample, you'll have to write a bunch of code if you want to turn that into a CMS.
For example, if you add some bold text, then you can't latter double click on it to edit that div because the code just looks at the parent node. There might be other issues, but that's just because it's a Proof of Concept, so you need to get your hands dirty and think a little.
Personally, I wouldn't recommend you to use that sample as is: if your code contains any javascript, then when you edit the text you'll have both the original script and the output of its execution, so it will turn into a big mess.
Re: CKEditor Div Replace
For example, if you add some bold text, then you can't latter double click on it to edit that div because the code just looks at the parent node. There might be other issues, but that's just because it's a Proof of Concept, so you need to get your hands dirty and think a little.
Personally, I wouldn't recommend you to use that sample as is: if your code contains any javascript, then when you edit the text you'll have both the original script and the output of its execution, so it will turn into a big mess.