问题
Is there the possbility to get the textual content of the clipboard to paste it automatically into a textarea clicking a button? Just found a method to copy data to it, but not to read data from it.
回答1:
No, you cannot do this in javascript because it has proven to be a huge security hole.
Likewise, the developers of Greasemonkey are unlikely to add this capability for the same reasons.
You can write a Firefox add-on that does this, but I've never seen a (legit) use case.
A technique that works well for me is to have the Greasemonkey script set focus to the textarea (or input) and then I merely press CtrlV. It's super convenient and actually faster than grabbing the mouse to click a button.
来源：https://stackoverflow.com/questions/23475342/get-clipboard-contents-with-greasemonkey