Underlying HTML
is inaccessible in the getData method: cf Copy RTF, Paste HTML, has extensive HT-markup, but getData sees trivial <BR>|<P> on \n....
(This is, why, onpaste=...getData... is 20x faster than browser-menu-Edit-Paste 1 min./MB.)
(This does not apply to browser-menu-Edit-Paste, but to paste clipboardData.getData().)
PS. Also note that MSIE 7 becomes reluctant at 1.5MB of DHTML-Element data, failing drag-selection of text, drag-and-drop move-text,...