When pasting a Word .doc or .rtf letter into a web form e.g into a textarea most of the document formatting (like bold or centering) is lost. Is there any way to do so without losing the formatting?
Not as long as you're using plain text areas: the textarea element is intended to carry only unformatted text. If you need formatted text, you could try a javascript framework providing such.
AFAIK, Dojo has an editor widget that could contain formatted text.