javascript - while 循环退出而不是返回循环 -Javascript

Question

试图只得到一个数字答案。内部 while 循环退出而不是返回到循环中。我不知道为什么。

var numPlays = prompt("How many games do you want to play?");
if (isNaN(numPlays) == true) {
    while (isNaN(numPlays) == true) {
        numPlays = prompt("That's not a number. Please pick a number.");
    }
} else if (numPlays == 0) {
    while (numPlays == 0) {
        numPlays = prompt("You have to at least play one game. Please pick a number.");
    }
} else if (numPlays == 1) {
    alert("OK! Let's play " + numPlays + " game!");
} else {
    alert("OK! Let's play best of " + numPlays + "!");
}

Answer 1

无需进入循环。

一个简单的例子

// Wrap in a function so we can start over
function start() {
  var numPlays = prompt("How many games do you want to play?");
  // edited this to check for 0
  if (isNaN(numPlays) || numPlays == 0) {
    alert('Nope, bad answer, try again!');
    return start();
  } else if (numPlays == 1) {
    alert('Ok, lets play 1 game!');
  } else {
    alert('Ok, lets play the best of ' + numPlays + 'games!');
    // A little aside
    // var neededToWin = (Math.floor((numPlays / 2)) + 1);
    // alert('Ok, you need to win ' + neededToWin + ' out of ' + numPlays + ' games to beat me!');
  }
}

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