Authentication System by using PHP

// Created by PhpStorm.
 // User: Tanzila Islam
 // Date: 7/7/15
 // Time: 4:07 AM

<?php
session_start();

$userinfo = array(
                'Mohita'=>'mohita',
                'Kitty'=>'kitty'
                );



if(isset($_POST['username'])) {
    if($userinfo[$_POST['username']] == $_POST['password']) {
        $_SESSION['username'] = $_POST['username'];
    }else {
        //Invalid Login
    }
}
?>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">

Name:<input type="text" name="username"> Password:<input type="password" name="password">
<input type="submit" name="submit" value="Log in"onclick="javascript: form.action='test1.php';" />

</form>

OUTPUT