how lock the height and width of the content?

Here's a quick solutions I thought of but it might not work right for you.

Try to put a <div> tag around your content on the site. Then make the style of this div that overflow is not allowed. So you would have:

<div style="overflow: hidden; height: yourheight; width: yourwidth;">your content from database</div>

I don't have much else that isn't very complicated.

I don't know of any way to put a max length on the editor. Maybe someone else knows.