改写留言板案例,适当添加CSS美化

<!DOCTYPE html>
<html lang="zh-cn">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>todolist:留言板</title>
  </head>
  <body>
    <input type="text" onkeydown="insertComment(this)" placeholder="请输入留言" autofocus />
    <ul class="list"></ul>
    <script>
      const insertComment = function (ele) {
        // console.log(enent);
        //  console.log(enent.type);
        //
        if (event.key === "Enter") {
          if (ele.value.length === 0) {
            alert("留言不能为空");
            ele.focus();
            return false;
          }
          const ul = document.querySelector(".list");
          ele.value += `<button onclick="del(this.parentNode)">删除</button>`;
          ul.insertAdjacentHTML("afterbegin", `<li>${ele.value}</li>`);
          ele.value = null;
        }
      };
      const del = function (ele) {
        return confirm("是否删除?") ? (ele.outerHTML = null) : false;
      };
    </script>
  </body>
</html>
运行结果