Question: Is there any open source low level web based editor ?
(I'm aware of wysiwyg editors like CKEditor, I'm looking for something different. )

* The editor should work in a way like [new Google Docs editor](https://drive.googleblog.com/2010/05/whats-different-about-new-google-docs.html).
* The editor should take user's input key by key and should build the text. so that the client JavaScript can have complete control while editing.
* Why i need it ? I need to build a DSL editor for my application with syntax highlighting and auto complete.
* I already found code editor ace <http://ace.ajax.org> . but it has lots of features that I don't need, so I'm searching for alternatives.
* I'm looking for similar lightweight editor, so that I can add my features (like autocomplete ) easily to it.

Answer: 
Have you seen Aloha Editor?

HTML5 and fast too:

<http://www.aloha-editor.org/>

It's open source there are no iframes and you can access the page contents just as they are.

It's the future of html editors.
There's collabedit:

<http://collabedit.com/>