How do I create a multiline non-scrolling textbox?

By "absolutely no scrolling behaviors" do you mean it shouldn't have a scrollbar?  Or, do you mean that when enough text is entered to fill the available space in the textarea that no more is allowed to be added?

If it's the former, some simple styling can accomplish what you want:

<textarea style="overflow: auto"></textarea>

However, as soon as sufficient text is entered to fill the box, scrollbars will appear.

If you meant the latter, that'll require an immensely more complex solution.

...unfortunately the immensely more complex solution.

Oh boy.  I was hoping you weren't going to say that as I'm not even sure if it's possible.   Perhaps if I understood the need for this better, I could suggest something that is doable.

I'm mimicing a standardized form that the user can fill out and print from the web. So, the fields for text entry are basically non scrolling boxes which correspond exactly to the sizes of the fields layed out on the old paper form.

Ive started looking at capturing keycodes within div tags that have been sized to the desired width and height, but the main problem I've run into with this approach is that the backspace button behaves badly (it causes the browser to go back to the last navigable page).