I have been playing various games at TeaGames.com which require using the arrows keys to move around.
Up until a few days ago, I could use them with no problem

, but now, when I move up and down with the arrow keys, the web page moves up and down as well so that the game area disappears

. How do I stop the arrow keys scrolling the web page?
I presume my children (or my daft sister in law) has changed some setting somewhere.