All-in-One Web form - php

Question

I'm learning PHP and I am now on creating an all in one web form that adds a new subscriber record to the subscribers table in the newsletter database. This is my first time on this site, so excuse any n00biness.
The comments explain the portion of code which determines whether the form will be processed. I'm not sure if it needs to go inside the if..else statement that validates the submitted form data, or if it goes after the validation in its own if..else.
When I put it inside the validation, the html form shows, but when I hit submit, all the info refreshes and nothing happens.
When I put it after the validation, the html form does not show, I get an error saying undefined variable: FormErrorCount. It then tells gives me the id number I'm supposed to get, but I did not enter a name or email (due to the html form not showing) and that is left blank.
There is an include file, but that is just fine.
I'm sure once this gets figured out, I will have the feeling to want to slap myself, but I have been staring at the screen way too long. Thank you
<?php
$ShowForm = FALSE;
$SubscriberName = "";
$SubscriberEmail = "";
if (isset($_POST['submit'])) {
$FormErrorCount = 0;
if (isset($_POST['SubName'])) {
$SubscriberName = stripslashes($_POST['SubName']);
$SubscriberName = trim($SubscriberName);
if (strlen($SubscriberName) == 0) {
echo "<p>You must include your name</p>\n";
++$FormErrorCount;
}
}else{
echo "<p>Form submittal error (No 'SubName' field)!</p>\n";
++$FormErrorCount;
}
if (isset($_POST['SubEmail'])) {
$SubscriberEmail = stripslashes($_POST['SubEmail']);
$SubscriberEmail = trim($SubscriberEmail);
if (strlen($SubscriberEmail == 0)) {
echo "<p>You must include your email address!</p>\n";
++$FormErrorCount;
}
}else{
echo "<p>Form submittal error (No 'SubEmail' field)!</p>\n";
++$FormErrorCount;
}
//CODE BELOW IS THE SAME AS THE COMMENTED OUT CODE TOWARDS THE END. NOT SURE WHERE IT GOES.
if ($FormErrorCount == 0) {
$ShowForm = FALSE;
include("inc_db_newsletter.php");
if ($DBConnect !== FALSE) {
$TableName = "subscribers";
$SubscriberDate = date("Y-m-d");
$SQLstring = "INSERT INTO $TableName " .
" (name, email, subscribe_date) " .
" VALUES('$SubscriberName', '$SubscriberEmail', '$SubscriberDate')";
$QueryResult = #mysql_query($SQLstring, $DBConnect);
if ($QueryResult === FALSE) {
echo "<p>Unable to insert the values into the subscriber table.</p>" .
"<p>Error code " . mysql_errno($DBConnect) . ": " .
mysql_error($DBConnect) . "</p>";
}else{
$SubscriberID = mysql_insert_id($DBConnect);
echo "<p>" . htmlentities($SubscriberName) . ", you are now subscribed to our
newsletter.<br />";
echo "Your subscriber ID is $SubscriberID.<br />";
echo "Your email address is " . htmlentities($SubscriberEmail) . ".</p>";
}
mysql_close($DBConnect);
}
}else{
$ShowForm = TRUE;
}
//CODE ABOVE IS THE SAME AS THE COMMENTED OUT CODE TOWARDS THE END. NOT SURE WHERE IT GOES.
}else{
$ShowForm = TRUE;
}
/* CODE BELOW IS SAME AS THE CODE BETWEEN THE COMMENTS ABOVE, BUT NOT SURE WHERE IT BELONGS
if ($FormErrorCount == 0) {
$ShowForm = FALSE;
include("inc_db_newsletter.php");
if ($DBConnect !== FALSE) {
$TableName = "subscribers";
$SubscriberDate = date("Y-m-d");
$SQLstring = "INSERT INTO $TableName (name, email, subscribe_date) " .
"VALUES ('$SubscriberName', '$SubscriberEmail', '$SubscriberDate')";
$QueryResult = #mysql_query($SQLstring, $DBConnect);
if ($QueryResult === FALSE) {
echo "<p>Unable to insert the values into the subscriber table.</p>" .
"<p>Error code " . mysql_errno($DBConnect) . ": " .
mysql_error($DBConnect) . "</p>";
}else{
$SubscriberID = mysql_insert_id($DBConnect);
echo "<p>" . htmlentities($SubscriberName) . ", you are now subscribed to our
newsletter.<br />";
echo "Your subscriber ID is $SubscriberID.<br />";
echo "Your email address is " . htmlentities($SubscriberEmail) . ".</p>";
}
mysql_close($DBConnect);
}
}else{
$ShowForm = TRUE;
}
*/CODE ABOVE IS SAME AS THE CODE BETWEEN THE COMMENTS ABOVE SECTION, BUT NOT SURE WHERE IT BELONGS
//HTML PORTION
if ($ShowForm) {
?>
<form action = "NewsletterSubscribe.php" method = "POST">
<p><strong>Your Name: </strong>
<input type = "text" name = "SubName" value = "<?php echo $SubscriberName; ?>" /></p>
<p><strong>Your Email Address: </strong>
<input type = "text" name = "SubEmail" value = "<?php echo $SubscriberEmail; ?>" /></p>
<p><input type = "Submit" name = "Submit" value = "Submit" /></p>
</form>
<?php
}
?>

Answer 1

Your code, ignoring for now the ShowForm part at the end, is structured like this:
if this is a submit {
validate the form data
if there are no errors {
save the form data
}
}
This looks reasonable. Maybe your form isn't being submitted as a POST? Check your <form action> and also use Firebug to make sure the form data is being submitted.
If you were to move the error check, you would have:
if this is a submit {
validate the form data
}
if there are no errors {
save the form data
}
And that's wrong because if the form were not being submitted, then you'd have no errors (hence the "undefined variable" error) and then it would attempt to save the nonexistent form data.