Countdown exercise

Build a very simple kitchen timer: modify the countdown() function in countdown.js to take a number of seconds, then print each second counting down to zero.

countdown(3);

// should print

// 3...
// 2...
// 1...
// 0

Levels

1. Use global variable to keep track of time
2. Keep track of time without defining any global variables
3. BONUS: don't define any new variables

Documentation

• setTimeout()
• setInterval()
• clearInterval()