请教高手：从Firefox 往文学城里的博克贴文章的问题

从Firefox 往文学城里的博克贴文章时,总是提示：

Unprivileged scripts cannot access Cut/Copy/Paste programatically for security reasons. Click OK to see a technical note at mozilla.org which shows you how to allow a script to access the clipboard.

我Clike了OK，并且按照做了，创建了user.js,可还是不行.请教高手,我需要如何做？
万分感激！