Workshop › Connect Four › Step 16 of 38

Playing with the keyboard

What we are doing

The keyboard can play too: the left and right arrows move the next disc, and Space or Enter drops it.

```js
document.addEventListener('keydown', (event) => {
  if (event.key === 'ArrowLeft') hoverCol = Math.max(0, hoverCol - 1)
  if (event.key === 'ArrowRight') hoverCol = Math.min(COLS - 1, hoverCol + 1)
  if (event.key === ' ' || event.key === 'Enter') {
    event.preventDefault()
    play(hoverCol)
  }
})
```

What it means

• event.key is the name of the key: 'ArrowLeft', ' ' (Space), 'Enter'...
• The arrows move hoverCol by one, kept between 0 and 6 with Math.max and Math.min.
• || means "or". preventDefault() stops Space from scrolling the page.

Your turn

Under the pointerdown listener write the keydown listener.

Skills: Keyboard and mouse input

← Whose turn? Keys 1 to 7 →

All steps

1. A dark background
2. A drawing function
3. The blue board
4. One hole
5. A whole row
6. All 42 holes
7. The board in memory
8. Discs in their colors
9. Draw every frame
10. Where does the disc land?
11. Play a column
12. Taking turns
13. Click to play
14. The next disc
15. Whose turn?
16. Playing with the keyboard
17. Keys 1 to 7
18. A disc on its way
19. Gravity
20. Watch it fall
21. Inside the board?
22. Walking along a line
23. Four in a row?
24. We have a winner
25. Circle the four
26. Who won?
27. A draw
28. Play again
29. Try a move and take it back
30. Win, or block
31. Don't help the player
32. Prefer the middle
33. The computer's turn
34. Only on your turn
35. You and the computer
36. Counting wins
37. Show the score
38. Build it yourself: the loser starts