After input form, how do you access the value that was input, into a variable later in the html/php file?

Question

I'll be thrilled with any solution that will do that. Here's what I've been trying:

I have an input form that gets variable info. I want to email using php mail(), the variable info that was input. I've put the php mail() later in the same html/php file (I haven't used js in here at all). I can't figure out how to access those input variable values, to put into the mail() function.

<form target="_blank" action="https://www.paypal.com/cgi-bin/webscr" method="post"> <br>
Donation Amount $: <input type="text" name="amount" size="20"> <br>
Instructions to us: 
<textarea name="eventcardinstructions" rows=6 cols=60></textarea><br>
<input type="hidden" name="add" value="1">
<input type="hidden" name="cmd" value="_cart">
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_cart_SM.gif" border="0" name="submit">
etc.
</form>  <!-- closes the form and lets the user hit a submit button-->

This is collecting inputs from the user to send to paypal. It's working. The user inputs an amount into an input field and instructions into a textarea. The amount is sent to paypal. The textarea instructions ARE NOT SENT to paypal, which is what I want.

Later (before the form ends OR) after end of form and the submit button that sends this to paypal, I want to reference the "amount" and "instructions" in php mail() function. The mail() function is working and sends emails. It just ignores and doesn't send the variable amounts. So the emails say:

     Subjectline: Event Card
     Body contents:  Event card bought for 

The mail function is:

    <?php   
     // headers allow the email to recognize html with in the 
     // message & process it.
    $headers = "MIME-Version: 1.0\r\n";          
    $headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";      
   $eventcardmsg = "Event card bought for " . $_POST['amount'];
   $eventcardmsg = $eventcardmsg .= $_POST['eventcardinstructions'];
   mail("email@ourdomain.net", "Event Card", $eventcardmsg, $headers);

?>

How do I setup amount and eventcardinstructions so the values are used?

I see a couple related q&as but can't figure it out from them. This answer is using it the same way I am by using the $_POST['variable']; but it's not working for me. https://stackoverflow.com/questions/30016669/how-do-you-save-a-inputs-value-in-a-variable

This one: Assign input form to a variable looks like it's using php in the middle of the html input form to set the variable. I could try that, but seems odd to need to, like I'm not understanding something.

Thanks!!

Answer 1

First, as TomasH already pointed, your $eventcardmsg assignation is wrong.
Anyway it might be simplified like this:

$eventcardmsg =
    'Event card bought for ' . $_POST['amount'] . ' ' . $_POST['eventcardinstructions'];

(don't omit at least one space between amount and instructions)

Now if you keep getting an wrong email content, the main question in this issue is: are POST query parameters sent to your PHP script?
So you should test it with something simple like:

<?php
echo '<pre>' . print_r($_POST, true) . '</pre>';

Then if it shows empty parameters (or even those parameters not cited), you must examine the way you're sending data from the HTML page.
Again already pointed by TomasH, it might be somme inconsistency while you previously send data to Paypal: if you don't identify it, please edit your question to show us the whole Paypal process.

---

EDIT (trying to answer the multiple OP's comments)

Regarding string concatenation in general
You may concatenate as many strings as you want into a resulting string, using the . operator, so:

$a = 'A';
$b = 'BB';
$c = 'CCC';
echo $a . $b . $c; // prints ABBCCC

Regarding .=
Any operator (not only .) may be used in conjunction with =, as a shortcut to avoid repeating the 1st operand when it is also the result, so:

$result .= $ope2;
// the above expression is pretty equivalent to the one below
$result = $result . $op2;

Regarding comments related to your original issue
It's not clear what you exactly want now, because you said:

I don't really want to send the form to a php file of my own.

But your original question tells you can't emit a proper email, and to emit an email you must first send the form to the php file where you emit it!

Anyway, you should test like I previously suggested:

echo '<pre>' . print_r($_POST, true) . '</pre>';

This way, you will get the whole list of which POST query parameters are passed to your script: print_r() is the function that prints this list, and <pre> is the enclosing HTML tag that makes this print more readable.

Be careful to type the statement exactly: from your penultimate comment, I guess you typed something wrong.