Is there a danger of my clipboard data being harvested by a web app or site that I visit?

I would like to stay safe, but I want to keep JavaScript enabled to give a better user experience.


Most modern browsers will not allow JavaScript to access your clipboard without at least a warning. It's plugins such as Flash that you need to worry about.

For more information, see MozillaZine's article which states:

By default, JavaScript is not allowed to read or set your clipboard data for security and privacy reasons. This is because websites scripts can erase and replace what you currently have in your clipboard (data loss issue) and they can read whatever you have in your clipboard (security and privacy issue); as such, you should grant access with caution.

There are extensions such as AllowClipboard Helper for Firefox which should let you decide exactly which sites have access to your clipboard.

  • or java applets ...
    – akira
    Jul 18 '10 at 17:17
  • @akira Untrusted Java applets should only get clipboard data if you explicitly copy/paste in that applet. Jul 28 '10 at 15:49

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