forms - Email send to 2 different locations in php

So, if you fill out this contact form i've got. Then, you'll fill out your return email just like every contact form out there. This variable is set to

 $from=$_POST["email"];
Copy code

So, I have a new feature in my contact form that enables users to send a copy of it to their email address that they submitted in the "email" section of the form. Except, I have this php code to take care of this for that user if they checked the box saying yes they wanted to...

if ($_POST['copy'] == "on") {
     $receiver = "my email addr" || $from;
 }
Copy code

with the name "copy" being the checkbox, here is that code now...

<div class="6u 12u$(small)">
    <input type="checkbox" id="copy" name="copy">
    <label for="copy">Email me a copy of this message</label>
</div>
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Now, idk if this is the problem, but when I submitted the form with "get" then checked the box for the copy then it came back in the url bar as "&copy=on".