I'm not sure, but several guesses: 1) The clipboard APIs aren't well known. 2) You can't normally set HTML content in the clipboard with IE since it only supports 'Text' and 'URL' types (http://msdn.microsoft.com/en-us/library/ms536744(v=vs.85).as...). 3) The IE interface (via window.clipboardData) might trigger an infobar. I didn't really test this though.