Clipboard Tester
Everything happens between your browser and this page: clipboard content is shown only to you and never leaves your device.
How it works
仕組みThis tool checks what your browser lets web pages do with the clipboard: write text to it, read text from it, and receive text you paste by hand. Each test runs only when you press its button, and the plates show the outcome plus the underlying permission state where your browser reports one. Clipboard rules differ sharply between Chrome, Firefox, and Safari, and between secure and plain pages, so the only way to know your own setup’s behaviour is to try it here. Anything read or pasted is displayed to you alone and never leaves your device.
Browsers treat the two directions very differently: writing text you already chose is low-risk, but reading could expose passwords or private notes you copied earlier. Chrome shows a permission prompt for reads, Safari only allows them in direct response to certain gestures, and Firefox doesn’t offer readText to normal pages at all; pasting with Ctrl+V is the sanctioned route there.
“granted” means the browser will allow the action silently, “prompt” means it will ask you first, and “denied” means it will refuse until you change site settings. “n/a” simply means your browser doesn’t report clipboard permissions through the Permissions API (Firefox and Safari mostly don’t), which is not itself a failure.
Not in a modern browser. Programmatic reads require a secure (https) page plus either an explicit permission grant or a direct user gesture, and paste events only fire when you actually press paste. The practical caution is the reverse direction: anything you copy can be pasted anywhere, so avoid copying secrets you don’t intend to paste.