<?php
session_start();

$host="";
$username="";
$password = "";
$database="";
    // create a database connection
    $connection = mysql_connect($host,$username,$password);
        if(!$connection){
            die("Database connection failed: " . mysql_error());
        }

    // select a database to use
    $db_select = mysql_select_db($database,$connection);
    if (!$db_select) {
        die("Database selectionfailed: " . mysql_error());
    }

    if(isset($_POST['submit'])){
        $username = mysql_real_escape_string($_POST['username']);
        $password = mysql_real_escape_string($_POST['password']);

        $query= mysql_query("SELECT id,username FROM user_info WHERE username='$username' AND password = '$password' LIMIT 1");
        $found = mysql_num_rows($query);
        if($found == 1){
            $row = mysql_fetch_assoc($query);
            //start sessioning the id and userame
            $_SESSION['id'] = $row['id'];
            $_SESSION['username'] = $row['username'];

            //header('Location: main.php'); //redirect page
            echo "you're login";
        }else{
            echo "login failed";
        }
    }
?>


<form method="POST" action="login.php">
    username <input type="text" name="username" id="username"><br/>
    password <input type="password" name="password" id="password"><br/>
    <input type="submit" id="submit" name="submit" value="login">
</form>