Taking data from 1 website(input) and pasting it to another website(input)

I need to take a data of username, then check in db, which aunthefecator user has got and depends on aunthefecator send him the window where he can enter it and login in his account!

I have tryed to make it like a 1 form and the method was sent to another form but it doesn not work

 <form name="logon" action="check_login.php" method="POST" id="login">
<input type="text" name="username">
<input type="password" name="password">
    <button type="submit">                               
        <span>Log IN</span>
    </button>

i just redirectimg on this page without getting data