​x
 
<!DOCTYPE html>
<html>
<body>
​
<ol id="myOl" start="50">
  <li>咖啡</li>
  <li>绿茶</li>
  <li>牛奶</li>
</ol>
​
<p>点击按钮返回有序列表的 start 属性的值。</p>
​
<button onclick="myFunction()">试一试</button>
​
<p id="demo"></p>
​
<script>
function myFunction() {
  var x = document.getElementById("myOl").start;
  document.getElementById("demo").innerHTML = x;
}
</script>
​
</body>
</html>
​