<?php
    session_start();
    if (isset($_POST["btnsubmit"]))
    {
        $nm=$_POST["username"];
        $pwd=$_POST["password"];
        $conn = new mysqli("localhost", "root", "", "simple_login");
    // Check connection
        if ($conn->connect_error)
        {
            die("Connection failed: " . $conn->connect_error);
    }

    $sql = "select * from member where username='$nm' and password='$pwd'" ;
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
//        to add sesssion value
        $_SESSION["memid"]=$row["mem_id"];
        $_SESSION["username"]=$row["username"];
        header("location:demo2.php");
        }
    } else { echo "wrong username or password" ; }