I am looking for a visual HTML editor script that works in browser basically. Its initial content will be generated from an existing URL and all the changes which will be done by the user, should be exportable in some kind of format. The aim here is reaching the final look later by applying this exported data.

The user here will be non-technical end user. The editor can be similar to WYSIWYG so user can switch between preview and code. The editor should not rely on some kind of special CSS/JS frameworks, it should be able to read from CSS and JS files directly from URL while generating the page.

There are lots of visual editors out there with lots of cool stuff. Some are using drag-and-drop UI elements, some are meant to work just with Bootstrap etc. But so far I could not find something I can use.

So if existing tools are not enough, I need to find a way of generate same result by comparing the outputs.

Beside taking diff of the contents, is there any method for generating the exportable changes for reapplying to initial HTML later?