PHP if / else statements don't seem to work for contact us with email - statements

Question

I've created some if / else statements to get a download when a user hit click
but dont work ,because you can direct download without field name or email ,please help me
contact. php for my site
http://my-easy-woodworking-projects.com
<?php
$field_name = $_POST['cf_name'];
$field_email = $_POST['cf_email'];
$field_message = $_POST['cf_message'];
$mail_to = 'lulu#yahoo.com';
$subject = 'Message from a site visitor '.$field_name;
$body_message = 'From: '.$field_name."\n";
$body_message .= 'E-mail: '.$field_email."\n";
$body_message .= 'Message: '.$field_message;
$headers = 'From: '.$field_email."\r\n";
$headers .= 'Reply-To: '.$field_email."\r\n";
$mail_status = mail($mail_to, $subject, $body_message, $headers);
if ($mail_status) { ?>
<script>
var str = "download";
document.write(str.link("http://www.myshedplans.com/12BY8SHED.pdf"));
</script>
<?php
}
else { ?>
<script language="javascript" type="text/javascript">
alert('Message failed. Please, send an email to gordon#template-help.com');
window.location = 'contact_page.html';
</script>
<?php
}
?>

Answer 1

I'm not quite sure why that if/else isn't working for you but one thing that can happen is the interpreter forgets about the if statement when it gets down to the else. A way to get around this is by echoing your html code within the conditional block like bellow:
<?php
if ($mail_status) {
echo "<script>";
echo "var str = \"download\";";
echo "document.write(str.link(\"http://www.myshedplans.com/12BY8SHED.pdf\"));";
echo "</script>";
}
else {
echo "<script language=\"javascript\" type=\"text/javascript\">";
echo "alert('Message failed. Please, send an email to gordon#template-help.com');";
echo "window.location = 'contact_page.html';";
echo "</script>";
}
?>