Show modal based on PHP variable - php

Question

I am having issues with displaying a modal when a user types a duplicate email or username, I have defined a boolean to store true when the modal should be shown and false when not. Even when I type a new username and email, the modal is still being shown and i am really confused why.
PHP:
if($checkUser->rowCount() > 0 || $checkEmail->rowCount() > 0){
$showModal = true;
}else{
$showModal = false;
HTML:
<?php if($showModal===false): ?>
<input type="submit" id="submit" name="submit" value="Register" readonly="readonly"/>
<?php else: ?>
<input type="" id="submit" name="submit" data-toggle="modal" data-target="#myModal" value="Register" readonly="readonly"/>
<div class="modal fade" id="myModal" role="dialog">
<div class="modal-dialog">
<!-- Modal content-->
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal">×</button>
<h4 class="modal-title">Registration Error!</h4>
</div>
<div class="modal-body">
<p>You have entered a Username or Email Address which has already been registered!</p>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
</div>
</div>
</div>
</div>
<?php endif; ?>
I remove the type 'submit' from the modal input as it was causing the modal to break as the page was being refreshed.
Any help is appreciated, thanks.