在数组的第2位置添加一个元素 - splice() - 在线编辑器

          <p id="demo">点击按钮向数组添加元素。</p>
<button onclick="myFunction()">点我</button>
<script>
  function myFunction() {
    var fruits = ["Banana", "Orange", "Apple", "Mango"];
    fruits.splice(2, 0, "Lemon", "Kiwi");
    var x = document.getElementById("demo");
    x.innerHTML = fruits;
  }
</script>
        