W3School TIY Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {font-family: Arial, Helvetica, sans-serif;}
* {box-sizing: border-box;}

/* 用于打开联系表单的按钮 - 固定在页面底部 */
.open-button {
  background-color: #555;
  color: white;
  padding: 16px 20px;
  border: none;
  cursor: pointer;
  opacity: 0.8;
  position: fixed;
  bottom: 23px;
  right: 28px;
  width: 280px;
}

/* 弹出表单 - 默认隐藏 */
.form-popup {
  display: none;
  position: fixed;
  bottom: 0;
  right: 15px;
  border: 3px solid #f1f1f1;
  z-index: 9;
}

/* 为表单容器添加样式 */
.form-container {
  max-width: 300px;
  padding: 10px;
  background-color: white;
}

/* 全宽输入字段 */
.form-container input[type=text], .form-container input[type=password] {
  width: 100%;
  padding: 15px;
  margin: 5px 0 22px 0;
  border: none;
  background: #f1f1f1;
}

/* 当输入框获得焦点时，执行某些操作 */
.form-container input[type=text]:focus, .form-container input[type=password]:focus {
  background-color: #ddd;
  outline: none;
}

/* 为提交/登录按钮设置样式 */
.form-container .btn {
  background-color: #04AA6D;
  color: white;
  padding: 16px 20px;
  border: none;
  cursor: pointer;
  width: 100%;
  margin-bottom:10px;
  opacity: 0.8;
}

/* 给取消按钮添加红色背景色 */
.form-container .cancel {
  background-color: red;
}

/* 为按钮添加一些悬停效果 */
.form-container .btn:hover, .open-button:hover {
  opacity: 1;
}
</style>
</head>
<body>

<h2>弹出式表单</h2>
<p>点击页面底部的按钮可打开登录表单。</p>
<p>请注意，按钮和表单是固定的 - 它们将始终位于浏览器窗口的底部。</p>

<div class="form-popup" id="myForm">
  <form action="/action_page.php" class="form-container">
    <h1>Login</h1>

<label for="email"><b>Email</b></label>
    <input type="text" placeholder="Enter Email" name="email" required>

<label for="psw"><b>Password</b></label>
    <input type="password" placeholder="Enter Password" name="psw" required>

<button type="submit" class="btn">Login</button>
    <button type="button" class="btn cancel" onclick="closeForm()">Close</button>
  </form>
</div>

function closeForm() {
  document.getElementById("myForm").style.display = "none";
}
</script>

</body>
</html>