Popup Window and PHP form

<form name="form1" method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>"

$('#submit').click(function(){
   load(external.php);  //where your script is
});

<input type='submit' onclick='alert("Message sent!")' />

<input type='submit' onclick='sendMessage()' />

function sendMessage(){
    $.ajax({
        //your stuff
    });
    $('.message').modal();
}

<?php

// Check if coming from a POST
if ($_SERVER['REQUEST_METHOD']=='POST' && isset($_POST['submit'])) {
    $name = $_POST['name'];
    $email = $_POST['email'];
    $message = $_POST['message'];
    $from = $email; 
    $to = '[email protected]'; 
    $subject = 'New Message';
    $human = $_POST['human'];

    $body = "From: $name\n E-Mail: $email\n Message:\n $message";

    if ($_POST['submit']) {
        if ($name != '' && $email != '') {
            if ($human == '4') {                 
                if (mail ($to, $subject, $body, $from)) { 
                    echo '<h4>Your message has been sent!</h4>';
                } else { 
                    echo '<h4>Something went wrong, go back and try again!</h4>'; 
                } //endif
            } else if ($_POST['submit'] && $human != '4') {
                echo '<h4>You answered the anti-spam question incorrectly!</h4>';
            }
            } else {
                echo '<h4>You need to fill in all required fields!!</h4>';
            } //endif
        } //endif

} //endif

?>
<form method='post' action='<?php echo $_SERVER['PHP_SELF']; ?>' >

    <label>Name</label>
    <input name="name" placeholder="Type Here" value="<?php if (isset($_POST['name'])) { echo $name;} ?>" >
    <label>Email</label>
    <input name="email" placeholder="Type Here" id="email" value="<?php if (isset($_POST['email'])) { echo $email;} ?>">
    <label>Message</label>
    <textarea name="message" placeholder="Type Here"><?php if (isset($_POST['message'])) { echo $message;} ?></textarea>


    <label>Human Verification</label>
        <input name="human" placeholder="2 + 2 = ? " id="human" value="<?php if (isset($_POST['human'])) { echo $human;} ?>">
        <input id="submit" name="submit" type="submit" value="Submit">
    </label>     
</form>