ENABLING JAVASCRIPT
TO PLAY THESE GAMES
 
Kindles
From your list of books press Menu and go to Experimental.
Under Web Browser press Launch Browser
The Browser opens, now press Menu and Browser Settings.
Click the item so you read Enable Browser the Back.

Paperwhite Kindles
Go to the Menu and then Browser Settings to enable Javascript.

Kindle Fires
In the browser click the Menu icon (a ladder) and select Settings.
Scroll down to see Enable JavaScript and check it. 
If you get stuck read your manual on how to active JavaScript.