Well dilettante,
Regarding msdn library...I do know how to use it, if fact use it quite a bit, along with many other reference web sites, regarding the ref's you gave...
One, the typical onkeypress or onkeydown commands, from my experience, are written as part of a field command such as <input type='text' name='somthing' onkeypress="if (event.keycode = 55)...etc...however this is not going to solve the backspace problem moving the page in history because you already have the focus on a form element....however, I seam to have problems getting the backspace key to register anyway with that command and cannot seam to block the key value...which goes in with a problem with the next point of that the javascript (or whatever you use) will have ot be written for the page, which still cannot seam to register the backspace button for an onkeypress, onkeydown, or onkeyup...the three I have tried. I've tried this with IE 5.5 sp2, and NS 6.02.
Perhaps you, or someone else, have had better luck? If so, perhaps you could provide specific code showing an example of it as I would be interested on how you made it work.
Additionally, as-far-as the 'freebsd' issue is concerned, you are correct that the specific operating system wouldn't effect the outcome of the (d)html provided within the web site, and my mind was crossing projects we're working on here, so please forgive me for that mistake. P-)
-Ovatvvon :-Q