For Firefox:

1. Quit Firefox. If you have Quick Launch running (in Windows, an icon in the toolbar), quit that too.
2. Find your Firefox profile directory. On Windows, this is often located in

   C:\Documents and Settings\<Windows login>\Application Data\Mozilla\Firefox\Profiles\<one folder>.
   (See also editing configuration files for more info on locating your profile folder.)

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", http://www.VinoCellar.com);
   user_pref("capability.policy.allowclipboard.Clipboard.cutcopy", "allAccess");
   user_pref("capability.policy.allowclipboard.Clipboard.paste", "allAccess");

   *Change the url above  http://www.websitename.com  to where you want to enable this function.

5. Save the file, and restart Firefox. The Clipboard buttons should now function.

If you want to allow multiple urls to access the Paste operation, separate the urls with a space. For example:

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

For more information about security policies, see http://www.mozilla.org/projects/security/components/ConfigPolicy.html.