给一个PHP用户登录代码（我这个写的不全）

Question

<?php include("conn_php.php");?>
<?php
$username=$_POST["username"];//用户名
$password=MD5($_POST["passwd"]);//密码
//$verifycode=$_POST["verifycode"];//验证码
$sql="SELECT * FROM admin_logon WHERE username='$username' || password='$password'";
$query=mysql_query($sql,$conn);
$row=mysql_fetch_array($query);  if(mysql_num_rows($query))
   
{   if($row[username]==$username and $row[password]==$password)

{
  header("location:admin_index.php");
  exit();
  } 

else  {
 $erro="用户名密码错误!";
}
  }?>

Answer 1

参考吧，看懂意思就行了，最好写成类
session_start();
if (!isset($_POST['UserName'])||(!isset($_POST['PassWord']))){
session_destroy();
exit();//无提交参数
}
if (!empty($_POST['UserName'])&&(!empty($_POST['PassWord']))){
$UserName=$_POST['UserName'];
$PassWord=$_POST['PassWord'];
}else{
session_destroy();
exit();//空值
}$SQL="SELECT Id FROM UserTable WHERE UserName='".$UserName."' AND PassWord='".$PassWord."'";
$Mysql->Query($SQL);
$Row=$Mysql->db_num_rows();
if ($Row>0){
$UserId=$Mysql->fetch_assoc();
}
if (empty($UserId['Id'])){
session_destroy();
exit();//用户名密码不符
}else{
$_SESSION['UserLoginID']=$UserId['Id'];//全局变量
}
//通过验证

Answer 2

if (!isset($UserId['Id'])||(empty($UserId['Id']))){
  session_destroy();
    exit();//用户名密码不符
}else
...

Answer 3

后面补充发了个代码 怎么不见了...我擦这个 CSDN