系统提示break非法 为什么啊

Question

 <script>
    var words=[
      "javascript",
      "monkey",
      "amazing",
      "pancake"
    ];
    var word=words[Math.floor(Math.random()*words.length)];
    var answerArray=[];
    for(var i=0;i<word.length;i++){
      answerArray[i]="_";
      }
    var remainingLetters=word.length;
    while(remainingLetters>0){

    };

    alert(answerArray,join(" "));
    var guess=prompt("Guess a letter,or click cancle to stop playing.");
    if(guess===null){
      break;
    }else if(guess.length !==1){
      alert("please enter a single letter.");
    }else{
    for(var j=0;j<word.length;j++){
      if (word[j]===guess) {
        answerArray[j]=guess;
        remainingLetters--;
        }
      }
    }
  }
    alert(answerArray.join(""));
    alert("Good job! The answer was "+word);

  </script> 

Answer 1

因为break不在循环或者switch里，你定义一个函数，用return