Updated button.html to use hostname from browser rather than localhost.

Author: mos2

Diff for: public/button.html

@@ -7,7 +7,7 @@
       <script type="text/javascript">
         $(document).ready(function() {
           $('#server_button').click(function() {
-            $.get('http://localhost:4000/', function(data) {
+            $.get('http://' + document.location.hostname  + ':4000', function(data) {
               $('#response_data').html(data); // show the list
             });
           });