php cookie

<?php

session_start();

include('phpconnectivity.php');

$nm=$_REQUEST['nm'];

$_SESSION['username']=$nm;

$pwd=$_REQUEST['pwd'];

$button=$_REQUEST['bt'];

$ck=$_REQUEST['ck'];

if(isset($button)){

    $query="select * from userinfo where name='{$nm}' and pass='{$pwd}'";

    $r=mysqli_query($con,$query);

    $r_count=mysqli_num_rows($r);

    echo $r_count;

    if($r_count>0){

        if(!empty($ck)){

            setcookie("loginuser",$nm,time()+(1*60*60));

            setcookie("loginpassword",$pwd,time()+(1*60*60));

        }

        else{

            

            if(isset($nm)){

                setcookie("loginuser","");

               

               }

               if(isset($pwd)){

                setcookie("loginpassword","");

               } 

        }

        header("Location: Home.php");

    }

    else{

        echo "this name or password not matched";

    }

}

...