<p>点击按钮来创建 OL 元素和 LI 元素。</p>
<button onclick="myFunction()">试一下</button>
var x = document.createElement("OL");
x.setAttribute("id", "myOl");
document.body.appendChild(x);
var y = document.createElement("LI");
var t = document.createTextNode("咖啡");
document.getElementById("myOl").appendChild(y);