Actually works, unlike some other similar extensions. Thanks.
Only problem is there doesn't seem to be any way to turn off the feature without disabling the entire extension. But I only needed it enabled once (to take a clean screenshot) and this is the only one that worked (without even having to refresh the page) so it gets 5 stars.

效果很完美

damn great! thanks!

does not work at all

It works super great! Just wish you could add a hotkey to turn it on/off. It would be so helpful.