What's this supposed to do? On Firefox/Win it just saves the initial blank page as you'd expect, which is not very useful. Removing the `contenteditable` attribute before saving makes no difference.
I'm not aware that there is a simple portable way to save dynamically-modified webpages; projects like TiddlyWiki have been banging their collective heads against this problem since forever.
You might be interested in a new way to create websites I'm creating. Websites are stored as JSON, and a small Javascript engine file writes these directly to the DOM.
This makes the site very easy to dynamically modify and save, which is the basis for this as a hosting service - the site itself contains a site editor that outputs the site as JSON, and uploads itself to S3.
(It's in late alpha, and will hopefully move to beta before the end of the month.)
Making Node or similar a prerequisite kills that value proposition stone dead, never mind piling on things like S3 as backends.
This is true for this new system as well. The browser engine is only needed to write JSON to the DOM, since browsers don't natively read JSON. You could host both on your SSD and point a webpage at them. (XHR caching is a to-do item.)
S3 is used because it's relatively common and trusted. Node (or any server) is just used to facilitate writing to S3. Node specifically is used because it's simpler to develop everything in one language, and that's the only language that runs in browsers.