Security preferences

Changing the preferences in Firefox

1. Quit Firefox. If you have Quick Launch running (on Windows, this is an icon in the toolbar), quit that too.
2. Find your Firefox profile directory.
3. Open the user.js file from that directory in a text editor. If there's no user.js file, create one.
4. Add these lines to user.js:

   user_pref("capability.policy.policynames", "allowclipboard");
   user_pref("capability.policy.allowclipboard.sites", "https://www.mozilla.org");
   user_pref("capability.policy.allowclipboard.Clipboard.cutcopy", "allAccess");
   user_pref("capability.policy.allowclipboard.Clipboard.paste", "allAccess");

5. Change the url https://www.mozilla.org to the site for which you want to enable this function.
6. Save the file and restart Firefox. The Clipboard buttons should now function.

user_pref("capability.policy.allowclipboard.sites", "https://www.mozilla.org")

user_pref("capability.policy.allowclipboard.sites", "https://www.mozilla.org")

If you want to allow multiple URLs to access the Paste operation, separate the URLs with a space. For For more information about security policies, see this article about Configurable Security Policies.See also