?????? ??? ???? ??? ???????. ??? ??? ??? ????? ?? ??? ???? ???? ???.

<?php
$SQL = "INSERT INTO `admin` (`username`, `password`) VALUES('admin', '123456')";
?>

??? ??, ???? ? ?? ??? ?? ?????

?? ?? ???? SQL ?? ?? ?????? ??? ?????.

??? ??? ??? ??????? ??? ??? ??? ???? ?? ?? ??? ???? ??????.

???? POST? ?? ???? ????.

<?php
if($_POST["Submit"])
{
   $username=$_POST["username"];
   $pwd=$_POST["pwd"];
   $code=$_POST["code"];
   if($code<>$_SESSION["auth"])
   {
      echo "<script language=javascript>alert('驗證碼不正確！');window.location='login.php'</script>";
      ?>
      <?php
      die();
   }
   $SQL ="SELECT * FROM admin where username='$username' and password='$pwd'";
   $rs=mysqli_query($link,$sql);
   if(mysqli_num_rows($rs)==1)
   {
      $_SESSION["pwd"]=$_POST["pwd"];
      $_SESSION["admin"]=session_id();
      echo "<script language=javascript>alert('登陸成功！');window.location='admin_index.php'</script>";
   }
   else
   {
      echo "<script language=javascript>alert('用戶名或密碼錯誤！');window.location='login.php'</script>";
      ?>
      <?php
      die();
   }
}
?>

?? ??? ??? ??(??)? ?? ??? ????? ??? ??(??)? ??? ???? ? ?????.

?? ??? ???? ???? ??? ??? PHP $_SESSION ??? ???? ??? ??? ??? ??? ??? ??? ????? ????. ??? ???? ???? ?????.