login code

<meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="css/bootstrap.min.css">
  <link rel="stylesheet" href="css/all.css">
  <script src="js/jquery.min.js"></script>
  <script src="js/bootstrap.min.js"></script>



<?php include "navbar.php";

session_start();
if (isset($_SESSION['un']))
{
header("Location:dashboard/index.php");
}
else{
    session_destroy();
}
 include "dcon.php";

 if(isset($_REQUEST["submit"]))
{
    $k=$_REQUEST['email'];
    $l=$_REQUEST['pass'];
    $pass=md5($l);
    $sql="SELECT * FROM `clientregister` WHERE c_mail='$k' AND c_pass='$pass'";
    $a=mysqli_query($conn,$sql);
    $rec_user=mysqli_fetch_array($a);
    $total=mysqli_num_rows($a);

    if($k=='' and $l=='')
    {
        $blank="please enter username/password";
    }
    else
    {

            if($total==1)
        {
            $_SESSION['un']=$rec_user['c_mail'];

            header("location:dashboard/index.php");
        }
        else
        {
            $message="please you have entered wrong username/password !";
        }
    }
}

?>

 <div class="container">



<div class="row justify-content-center">
<div class="col-md-6">
<div class="card">
<header class="card-header">
    <a href="register.php" class="float-right btn btn-outline-primary mt-1">Sign Up</a>

    <?php   echo "<div class=' alert-info'><font color='red'>".$message."</font></div>"; ?>
    <?php   echo "<div class=' alert-info'><font color='red'>".$blank."</font></div>"; ?>
    <h3 class="card-title mt-2">Log In</h3>
</header>
<article class="card-body">
<form action="login.php?action=submit" method="post">
    <div class="form-row">
        <div class="col form-group">
            <label>EMAIL ID </label>
            <input type="email" class="form-control" name="email" placeholder="Enter your email "   >
        </div> <!-- form-group end.// -->

    </div> <!-- form-row end.// -->


    <div class="form-group">
        <label>PASSWORD</label>
        <input class="form-control" type="password" name="pass" placeholder="Enter your password">
    </div> <!-- form-group end.// -->
    <div class="form-group">
        <button type="submit" class="btn btn-primary btn-block" name='submit'>LOG IN   </button>
    </div> <!-- form-group// -->

</form>
</article> <!-- card-body end .// -->
<div class="border-top card-body text-center">Forgot Password ? <a href="#">Click Here</a></div>
</div> <!-- card.// -->
</div> <!-- col.//-->

</div> <!-- row.//-->


</div>