Написал всё до этого момента и вот следующий 6 шаг - запустить )
6. Let's test what we just coded. Save all the files and open index.html in the
web browser.
7. Try pressing the keys to control both paddles. The two paddles should move
smoothly and respond at the same time without interruption.
What just happened?
We have used another approach to capture the keyboard input. Instead of doing the action
once after the key press is detected, we store which keys are pressed and which are not.
Afterwards, we use a JavaScript interval to check the pressed keys every 30 milliseconds.
This approach enables us to know all the keys pressed at the time and so we can move both
paddles at the same time.
