Making custom messages notification counter

Sometimes you need to create custom unread messages counter at your website.

This is example of jQuery code snippet to make counter display messages count dynamically:

<script type="text/javascript">
jQuery(document).on('bp-better-messages-update-unread', function( event ) {
   var unread = parseInt(event.originalEvent.detail.unread);
   if( isNaN ( unread ) || unread < 0 ) unread = 0;
   var messages_count = jQuery('.header-notifications.user-messages span');
   if( unread > 0 ){
       messages_count.text(unread).attr('class', 'count');
   } else {
       messages_count.text(unread).attr('class', 'no-alert');
   }
});
</script>