diff --git a/network/mx.php b/network/mx.php
index 332150a..603dbce 100644
--- a/network/mx.php
+++ b/network/mx.php
@@ -1,51 +1,51 @@
 <?php
 	$mail = '';
 	if (isset($_REQUEST['mail'])) {
 		$mail = $_REQUEST['mail'];
 	}
 ?>
 <h2>Search</h2>
 <form>
 <div class="row collapse">
   <div class="ten mobile-three columns">
     <input type="text" name="mail" id="mail" value="<?= $mail ?>" placeholder="Enter e-mail address here." />
   </div>
   <div class="two mobile-one columns">
     <input type="submit" class="button expand postfix" value="Search" />
   </div>
 </div>
 </form>
 <?php
 function is_domain ($string) {
-	return preg_match($string, '/[a-zA-Z\d-]{,63}(\.[a-zA-Z\d-]{,63})*/');
+	return preg_match('/[a-zA-Z\d-]{,63}(\.[a-zA-Z\d-]{,63})*/', $string);
 }
 
 function print_mx ($domain) {
 	if (getmxrr($domain, $mxhosts, $weights)) {
 		echo '<table id="mx" class="result">';
 		echo '<tr><th>Host</th><th>Weight</th></tr>';
 		$n = count($mxhosts);
 		for ($i = 0 ; $i < $n ; $i++) {
 			echo "<tr><td>$mxhosts[$i]</td><td>$weights[$i]</td></tr>";
 		}
 		echo '</table>';
 	} else {
 		echo '<p id="mx" class="result emptyresult">—</p>';
 	}
 	echo "<h3>Determination method</h3>\n<p><strong>DNS lookup:</strong> $domain MX ?</p>";
 }
 
 if ($mail) {
 	echo "<h2>Result</h2>\n<h3>MX records</h3>";
 	if (is_mail($mail)) {
 		//Gets domain name
 		$data = explode('@', $mail);
 		print_mx($data[1]);
 	} elseif (is_domain($mail)) {
 		//We silently accept direct domain entries given instead of a mail
 		print_mx($mail);
 	} else {
 		echo "<h3>Error</h3>\n<p class='error'>$mail isn't a valid mail address.</p>";
 		echo "<h3>Improve this tool</h3><p>This code is open source, you can improve it. Fork it and add JS validation mail code. If the mail is wrong, apply the class .error to the input box.</p>";
 	}
 }