Why does my php 'else' displays both at once? - php

Question

I have this php code which determines if the user has already voted or not.
$row_content['Vote_Who'] contains a list of all users who have previously voted, and is formatted like "User_1 User_2 User_3"
$_SESSION['Username'] is the current username of the user who is signed in. Yes this works, as I have called it elsewhere on the page.
<?php if(strpos($row_content['Vote_Who'], $_SESSION['Username']) !== false){?>
<input type="button" value="Thanks for voting!">
<?php }
else{ ?>
<input type="submit" value="<?php echo $row_content['Votes']?>: Vote Up! ▲" width="75px">
<input type="hidden" name="MM_update" value="vote">
<?php } ?>
But when I see the result in the web browser, both the buttons are displayed at once.
How can I fix that?
Thanks in advance.
UPDATE: Image that proves both buttons display at the same time
UPDATE:
Full code section:
<?php
if ($totalRows_content > 0){
do {?>
<table width="100%">
<tr>
<td width="75px" height="75px" align="right">
<img src="<?php echo $row_content['User_Pic']?>" width="50px" height="50px">
<br />
<?php echo $row_content['Author']?>
</td>
<td colspan="2">
<h2>
<?php echo $row_content['Title']?>
</h2>
</td>
</tr>
<tr>
<td>
</td>
<td style="vertical-align:top">
<h3>
<?php echo $row_content['Content']?>
<br />
<br />
</h3>
</td>
<td width="150px" style="vertical-align:top">
<img src="<?php echo $row_content['Picture']?>" style="max-width:150px; max-height:100px">
<h3>
<?php echo $row_content['Published']?>
</h3>
<br />
<?php if(isset ($_SESSION['Username'])){?>
<form method="POST" action="<?php echo $editFormAction; ?>" name="vote">
<input type="text" hidden="hidden" name="ID" value="<?php echo $row_content['ID']?>">
<input type="text" hidden="hidden" name="votes_up" value="<?php echo ($row_content['Votes'] + 1)?>">
<?php if(strpos($row_content['Vote_Who'], $_SESSION['Username']) !== false){?>
<input type="button" value="Thanks for voting!">
<?php }
else{ ?>
<input type="submit" value="<?php echo $row_content['Votes']?>: Vote Up! ▲" width="75px">
<input type="hidden" name="MM_update" value="vote">
<?php } ?>
</form>
<a href="comments.php?ID=<?php echo $row_content['ID']?>">
<input type="button" value="See Comments">
</a>
<?php }
else{?>
<?php echo $row_content['Votes']?> Votes - You must be signed in to vote
<?php }?>
</td>
</tr>
</table>
<?php }while ($row_content = mysql_fetch_assoc($content));}
else{?>
there is nothing
<?php }
?>

Answer 1

The problem was where I'd used the operator of
!==
when what I should have used was
!=
Example:
strpos($row_content['Vote_Who'], $_SESSION['Username']) != false
Thanks to everyone who offered assistance with this issue.