代码示例:(标识:jsck_state_for_arr)
<!DOCTYPE html>
<html>
<body>

<p>单击该按钮可按升序循环遍历数组的索引。</p>

<button onclick="myFunction()">试一试</button>

<p id="demo"></p>

<script>
function myFunction() {
  var cars = ["BMW", "Volvo", "Saab", "Ford"];
  var text = "";
  var i;
  for (i = 0; i < cars.length; i++) {
    text += cars[i] + "<br>";
  }
  document.getElementById("demo").innerHTML = text;
}
</script>

</body>
</html>
运行结果: