A couple small changes for this. First, monitor keydown instead of keyup event. This allows you to preventDefault and keep the new text from being added.
Next, you have to allow delete and backspace so that they can correct their mistake. There are a lot of corner cases that you should probably account for like cut/paste, arrow keys, etc. That's why I don't like modifying the default behavior for the text area on something like this. You should always do pretransmit and server side double checking anyways so I don't think it gets you a lot other than the potential to annoy your users.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.