Let's see, let me count the ways to copy and paste (and this is only Windows!)
1) Ctrl + C | Ctrl + V
2) Ctrl + Ins | Shift + Ins
3) Right-click >> Copy | Right-click >> Paste
4) Select text | Ctrl-drag'n'drop
5) Edit >> Copy | Edit >> Paste
You can't directly prevent #5, and you can possibly do something about 1-4, but not without a lot of headache.
Personally, I don't think it's worth the effort.
If you MUST have a solution, then I can only offer this IE5+ fix
<input type="text" onpaste="event.returnValue=false" ondrop="event.returnValue=false"/>
However, you'll likely make people think you're site is busted and just piss them off. I don't recommend this, but there it is.
And, of course, Mozilla et al., Opera, etc won't be affected by this fix.
Last edited by beetle; 07-11-2003 at 05:15 PM..