I tried to make a simple contact form via 
HTML and PHP but the form doesnt seem to submit. it stays on the 
HTML page and doesnt post to the php form. would love someone to look over the code, thanks in advanced. 
simple_form.
html cdoe
    <!DOCTYPE 
html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Simple Feedback Form</title>
</head>
<body>
<form action="send_simpleform.php" method="post">
<p>Your name<br />
<input name="sender_name" type="text" size="30" /></p>
<p>Email<br  />
<input name="sender_email" type="text" size="30" /></p>
<p>Message<br />
<textarea name="message" cols="30" rows="5"></textarea></p>
<input name="submit" type="button" value="Send This Form" />
</form>
</body>
</html>
send_simpleform.php code
<?
if (($_POST[sender_name] == "") || ($_POST[sender_email] == "") || ($_POST[message] == "") {
    header("Location: simple_form.php");
    exit;
}
$msg = "Email sent from wwwsite\n";
$msg .= "Sender's Name:\t $_POST[senders_name]\n";
$msg .= "Sender's E-mail:\t $_POST[senders_email]\n";
$msg .= "Sender's Message:\t $_POST[message]\n";
$to = "
[email protected]";
$subject = "Website feedback message";
$mailheaders = "From: My web site <www.testwebsite.com>\n";
$mailherders .= "Reply to: $_POST[sender_email]\n";
$mail($to, $subject, $msg, $mailheaders);
?>
<!DOCTYPE 
html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Simple Feedback Form Sent</title>
</head>
<body>
<h1>The following email has been sent</h1>
<p>Your Name:<br />
<? echo "$_POST[sender_name]"; ?>
<p>Your Email Adress:<br />
<? echo "$_POST[sender_email]"; ?>
<p>Message:<br />
<? echo "$_POST[message]"; ?>
</p>
</body>
</html>