login.php

<?php
include("config.php");
session_start();
if($_SERVER["REQUEST_METHOD"] == "POST")
{
// username and password send from Form
$myusername = mysqli_real_escape_string($db, $_POST['username']);
$mypassword = mysqli_real_escape_string($db, $_POST['password']);

$sql = "SELECT * FROM radcheck WHERE username='$myusername' and value='$mypassword'";
$result = mysqli_query($db, $sql);
$row = mysqli_fetch_array($result, MYSQLI_ASSOC);
$active = $row['active'];
$count = mysqli_num_rows($result);
// If result matched $myusername and $mypassword, table row must be 1 row
if($count == 1)
{
$_SESSION['login_user'] = $myusername;
header("location: welcome.php");
}
else
{
$error = "Your Login Name or Password is invalid";
echo $error;
}
}
?>

<h1>Login Here</h1>
<form action="" method="POST">
<label>Account:</label>
<input type="text" name="username">
<br>
<label>Password:</label>
<input type="password" name="password">
<br>
<input type="submit" value="Submit">
</form>