​x
 
<!DOCTYPE html>
<html>
<body>
​
<p>单击该按钮可遍历名为“cars”的数组的索引。</p>
​
<button onclick="myFunction()">试一试</button>
​
<p id="demo"></p>
​
<script>
function myFunction() {
  var cars = ["BMW", "Volvo", "Saab", "Ford"];
  var i;
  for (i = 0, len = cars.length, text = ""; i < len; i++) {
    text += cars[i] + "<br>";
  }
  document.getElementById("demo").innerHTML = text;
}
</script>
​
</body>
</html>
​