javascript count down with wile loop

//declare and instantiate your variable
var timer = 60;

//set up your loop that will run while your variable is greater than zero
while (timer > 0) {
//log timer to the console for debugging purposes
console.log(timer);
//reduce the count of timer by one over each iteration
timer--;
}

//after timer has reached zero, the code will break out of the while loop and run the alert with your confirmation message
alert("Done");