Translation of welcome message

I use the chat plugin on two different websites, one English and one Norwegian. We only have one Facebook page. When I changed the welcome message to English during the plugin setup, the welcome message was also changed on the Norwegian website. The support of my WordPress theme tried to help me and suggested the following code for changing the welcome message on the Norwegian website, but it did not work.

<script>
(function($) {
 $(document).ready(function() {
 $("._909b ").text("Velkommen. Hva kan vi hjelpe deg med");
 });
})(jQuery);
</script>

The page I need help with: [log in to see the link]