Question

我创建了一个数组，当你点击随机单词按钮时会选择一个随机单词，但我仍然坚持创建下一个和上一个单词以便逐步完成列表。

<Script>
        window.onload = myFunction;

        var WordList = ["a", "b", "c", "d"];
        var Word

        function myFunction() {
        var Word = WordList[Math.floor(Math.random()*WordList.length)];
        document.getElementById("Word").innerHTML = Word;
        }

        function NextWord() {
        var a = WordList.indexOf("Word");

        document.getElementById("Word").innerHTML = a;

    </script>

Answer 1

你的nextWord（）函数没有右括号，你正在寻找字符串“Word”的索引，你宁愿看看indexOf变量Word，这样......

    function NextWord() {
      var a = WordList.indexOf(Word) ;

      /// check if last entry 
      if((a + 1) == WordList.length) {
         /// reset
         a = 0;
      }else {
         /// increment
         a += 1;
      }
      /// set innerhtml
      document.getElementById("Word").innerHTML = WordList[a];
    }

你可以为PreviousWord（）

做同样的事情

Answer 2

缓存数组的当前索引

var currentIndex = 0, wordList = ["a", "b", "c", "d"];

function randomWord() {
  currentIndex = Math.floor(Math.random() * wordList.length);
  return wordList[currentIndex];
}

function nextWord() {
  currentIndex += 1;
  currentIndex = Math.min(currentIndex, wordList.length - 1);
  return wordList[currentIndex];
}

function prevWord() {
  currentIndex -= 1;
  currentIndex = Math.max(currentIndex, 0);
  return wordList[currentIndex];
}

Javascript Next，Prev，Random from a array

2 个答案: