<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>