Javascript在while循环中评估多个条件

Question

下面的代码应不断询问用户从阵列中随机选择的一种乐器，直到他们正确使用为止。 它应该计算猜测的数量，并评估每个猜测，并确定其字母顺序高于还是低于随机。 由于某些原因，我的If语句似乎无法正常工作。 例如，如果我输入的物品不在列表中，则代码将不会按预期返回第1号警报。 即使正确输入了仪器，代码也不会返回任何内容，而是按预期返回上一个警报。 任何帮助是极大的赞赏。

var MyInstrument;
var guess_input_text;   
var guess_input;
var finished = false;   
var guess_counter = 0;

function My_instrument()
{
        var instruments = ['violin', 'drums', 'pipe', 'harp', 'xylophone'];
        instruments.sort();
        var randomInstrument = Math.floor(Math.random()*instruments.length);
        MyInstrument = instruments[randomInstrument];

        while (!finished) {
            guess_input_text = prompt("I'm thinking of one of these instruments \n" 
            + instruments + "\n can you guess which one it is?"
            );
            var guess_input = instruments.indexOf(guess_input_text);
            alert(guess_input);
            guess_counter++;
            finished = check_guess();
        }
}

function check_guess() 
{
        if (guess_input == -1)
        {
          alert("you have not entered instrument from the list");
          return false;
        }

        if (guess_input != -1 && guess_input_text > MyInstrument)
        {
          alert("your instrument is alphabetically higher than mine");
          return false;
        }

        if (guess_input != -1 && guess_input_text < MyInstrument)
        {
          alert("your instrument is alphabetically lower than mine");
          return false;
        }

        alert("You got it! The instrument was " + target + 
              ".\n\nIt took you " + guess_counter + " guesses to get it!");
        return true;
}

My_instrument();

Answer 1

在check_guess()最后一个警报中

target未定义

用MyInstrument替换