Cross-browser method to prevent all methods of text copying from a textarea?

Question

I am working on an online typing software. In the typing software, all is going well but I have the problem of dishonest users who might possibly type the text into the text

Answer 1

You maybe could do something like:

var txtArea = document.getElementById("YourTextAreaId");
txtArea.oncopy = function() { return false; } 
txtArea.onpaste = function() { return false; } 
txtArea.oncut = function() { return false; } 

But even then, the user can copy the content by other means, as suggested in your question.