textarea元素输入验证兼容版实例页面

展示

代码

• HTML：

  <textarea placeholder=" "></textarea><span></span>

• CSS：

  textarea {
      vertical-align: top;
      margin-right: 10px;
  }
  textarea:not(:empty) + span::before {
      content: "√";
      color: green;
  }
  textarea:not(:placeholder-shown) + span::before {
      content: "√";
      color: green;
  }