SOLVED: Form submitting data to new window and to two different pages

I have read page http://www.plus2net.com/html_tutorial/submit-two.php with great interest. I have tried the following code:

<form name="f1" type="post" action="EmailSend13.php">
<input type="text" name="subject" size="120" /><br /><br />
<input type='submit' value='Open default action file EmailSend13.php' onclick="this.form.target='_blank';return true;" />
<input type='submit' value='Open EmailSend14.php' onclick="f1.action='EmailSend14.php'; return true;" />
</form>

The form submits to the correct page but the input value of "subject" using:

<?php
$subject=$_POST['subject'];
print "EmailSend13.php<br />";
print "Subject: $subject";
?>

returns a blank. Can anyone help?