I’m looking to have one of these in an HTML page.

F12 developer tools calls this a wmd-edit control. I suppose this requires some extra library (wmd).
I’m looking to have something like this (not using some library) filling up the entire page, and read only.. is this possible, or must I use a library?
I’m quite new to experimenting with HTML.
You can use a
<textarea>. See http://jsfiddle.net/7YVZX/ for a demo.