<html>
<body>
<ol id="myList">
<li>Tea</li>
<li>Milk</li>
<li>Water</li>
</ol>
<p>点击按钮创建 LI 元素。</p>
<p id="demo"></p>
<button onclick="myFunction()">尝试一下</button>
<script>
function myFunction()
{
var x = document.createElement("LI");
var t = document.createTextNode("Coffee");
x.appendChild(t);
document.getElementById("myList").appendChild(x);
}
</script>
</body>
</html>