ผมว่ามันน่าจะต้องมี jQuery ด้วยครับ
ลองใส่เป็น
<script type="text/javascript">
document.write(unescape("<script src='" document.location.protocol "//ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js' charset='utf-8' type='text/javascript'></script>"));
</script>
<!--Start of Zopim Live Chat Script-->
<script type="text/javascript">
window.$zopim||(function(d,s){var z=$zopim=function(c){z._.push(c)},$=z.s=
d.createElement(s),e=d.getElementsByTagName(s)[0];z.set=function(o){z.set.
_.push(o)};z._=[];z.set._=[];$.async=!0;$.setAttribute('charset','utf-8');
$.src='//cdn.zopim.com/?1HXNbP4PqH8lqZMMvN1VJHmqco4mmsZc';z.t= new Date;$.
type='text/javascript';e.parentNode.insertBefore($,e)})(document,'script');
</script>
<!--End of Zopim Live Chat Script-->
ลองดูครับ