This looks like a fun experiment. Have you considered adding this as a Chrome plugin and make it "remember" what you drag? Also maybe implement some sort of "undo" mechanism as well?
No, but you can run it by pasting 'javascript:' in the URL bar, followed by the contents of http://staticresource.com/dragon.js or as a bookmarklet in Chrome, but the real intended browser I was hoping to use this on was Mobile Safari - to rearrange sites via touch on limited hardware. It also works flawlessly on a $50 Amazon Fire tablet too!
What I created it for was the ability to load up a site, rearrange it, screenshot it - and refresh to have it return to normal (either for more screenshots or to use it). One reason this won't do what you're thinking it will 'saving the location to where you have dragged it' is that it does unexpected things when you resize the browser. If your browser always remembered where you positioned things I think it would quickly end up broken :/
> Can you implement an undo?
I was thinking about this last night. It is possible (you could remember the previous values for the top and left, then set those values when a keyboard key is pressed) but again the big target for this script for my use will be browsers without keyboard (for an undo shortcut) so I'd also need to add an on-screen undo button. I'm still thinking about this and how to accomplish it.
Feel free to use the source as well, consider it under MIT license :)
Thanks for sharing.