I think the OP wants to place text in the clipboard. I do it all the time because it is so easy to mistype otherwise. And some peoples' posts are wordy, to put it mildly.

I did find Fakebook to be troublesome, maybe the FireFox update has addressed that. But I have noticed that my Excel/Word/Outlook macros have emptied the clipboard in ways I have yet to investigate. This came in about two Micro$oft updates ago.

PS Although there are about 180 JavaScript files in Farcebook I would bet there is a huge mountain of PHP (or equivalent) on their servers. If only to trawl for factoids about your profile and IMNSHO it ain't clever enough by a huge margin. But annoyingly too snoopy for my tastes.