用PHP写一个网站登录的实例

<form method="post" action="">
<div style="width:400px;height:400px;background:url(https://scpic.chinaz.net/files/pic/pic9/202111/apic36436.jpg);margin:0 auto;margin-top:100px;padding-top:180px;">
   <center> <div>请输入账号：</div>
    <input type="text" name="account" style=""></input>
    <div>请输入密码：</div>
    <input type="text" name="password"></input>
    <div style="margin-top:5px;"><button>立即登录</button></div></center>
</div>
</form>
<?php
  if(!empty($_POST)){
    # 判断传值
    if(empty($_POST['account'])){
      echo '<script>window.alert("请输入账号");history.back();</script>';
      return false;
    }
    if(empty($_POST['password'])){
      echo '<script>window.alert("请输入密码");history.back();</script>';
      return false;
    }

    # 账号查询
    $pdo = new PDO('mysql:host=localhost;dbname=boke', 'root' , 'root');
    $stmt = $pdo->prepare('SELECT * FROM admin WHERE `account`="'.$_POST['account'].'"');
    $stmt->execute();
    $admin = $stmt->fetchAll();
    $find = $admin[0];

    # 判断账号
    if(empty($find)){
      echo '<script>window.alert("账号不存在");history.back();</script>';print_r($admin);
      return false;
    }
    if($find['password'] != md5($_POST['password'])){
      echo '<script>window.alert("密码不正确");history.back();</script>';
      return false;
    }

    setcookie('id',$find['id']);
    setcookie('account',$find['account']);
    echo '<script>window.alert("登录成功");window.location.href="guanli.php";</script>';
    return false;
  }
?>

PS：登录表单很简陋，毕竟我的css水平也就这样了。php+mysql实现登录功能。