Workshop › Sudoku › Step 11 of 28

Write digits

What we are doing

Keys 1 to 9 write a digit in the selected cell; 0, Backspace or Delete erase it. The puzzle's own digits cannot be changed.

```js
function enter(d) {
  if (given[selected.r][selected.c]) return
  grid[selected.r][selected.c] = d
}

  } else if (event.key >= '1' && event.key <= '9') enter(Number(event.key))
  else if (event.key === '0' || event.key === 'Backspace' || event.key === 'Delete') enter(0)
```

What it means

• enter writes into the selected cell unless it is a given one; writing 0 erases.
• event.key >= '1' && event.key <= '9' compares texts: a single character between '1' and '9' is a digit key.
• Number(event.key) turns '7' into 7.

Your turn

1. Under the reset function, write enter.
2. In keydown, write the two else if lines after the arrow block.

Skills: Keyboard and mouse input, Game states

← Move with the arrows The three rules in one loop →

All steps

1. Nine by nine
2. Lines and boxes
3. A puzzle from a string
4. The puzzle's own digits
5. Keep drawing
6. The selected cell
7. Light up row, column and box
8. The same digit everywhere
9. Click to select
10. Move with the arrows
11. Write digits
12. The three rules in one loop
13. Show mistakes
14. Solved!
15. A clock
16. The solved message
17. Play again
18. The easiest cell
19. The solver
20. Random order
21. Invent a puzzle
22. A new puzzle every game
23. Hints
24. Best time
25. N for a new puzzle
26. A number pad
27. Tap the pad
28. Build it yourself: undo