Couldn't get to sleep last night, so I killed an hour or so by writing the code in the Unicode sliderule, mostly the functions _insert_a_char and ev_backspace, that deals with the current cursor position (or selected area) in the textbox. I use the selectionStart and selectionEnd and setSelectionRange methods, which don't seem to work under MSIE. So under MSIE, we always just pretend the cursor is at the end of the textarea.
Still couldn't sleep, so I listened to the Carse lecture. Mildly interesting.