Antispam - Hiding textbox

<form action="php/mailchimp-action.php" method="POST" >
    < div id="msg" > < /div >                   
    < input class="form-control" type="text" placeholder="Email address" name="email1" value="" >
    < div class="clear" > < /div >
    < !-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-- >
    < div style="position: absolute; left: -5000px;" aria-hidden="true" >
        < input type="text" name="b_b7ef45306f8b17781aa5ae58a_6b09f39a55" tabindex="-1" value="" >
    < /div >
    < div class="clear" >
        < button type="submit" name="submitbtn" id="mc-embedded-subscribe" class="button button-border mt-20 form-button" > Get notified < /button >
    < /div >
< /form >