<body>
  <input id="input" type="text" name="" id="">
  <button onclick="addContent()">添加</button>
  <ul id="ul"></ul>
  <script>
    function addContent() {
      let ul = document.getElementById('ul')
      let li = document.createElement('li');
      li.appendChild(document.createTextNode(document.getElementById('input').value))
      let mybutton = document.createElement('input');
      mybutton.type = "button";
      mybutton.value = "删除";
      mybutton.onclick = function () {
 deleteLi(lis.length);
      }
      li.appendChild(mybutton)
      ul.appendChild(li)
      document.getElementById('input').value = "";
    }

    function deleteLi(index) {
      let ul = document.getElementById('ul');
      ul.removeChild(ul.childNodes[index - 1]);
    }
  </script>
</body>