Prevent copying text in web-page

Here:
How to disable text selection highlighting using CSS?

-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
-o-user-select: none;
user-select: none;

Disallow them from being able to answer when the window’s onBlur event is fired. They can still use other devices, but they won’t be able to cheat on the same computer.