Chat com php e jquery

Boa tarde, estou trabalhando o chat box da biblioteca do jquery.ui

<script type="text/javascript" src="<?php echo URL . JS; ?>jquery.ui.chatbox.js"></script>
<script type="text/javascript">
 $(document).ready(function(){
 var box = null;
 $("#open_chat").click(function(event, ui) {
 if(box) {
 box.chatbox("option", "boxManager").toggleBox();
 }
 else {
 box = $("#chat_div").chatbox({
 id:"chat_div",
 user:{key : "value"},
 title : "Lanches Altas Horas Chat",
 messageSent : function(id, user, msg) {
 $("#log").append(id + " said: " + msg + "<br/>");
 $("#chat_div").chatbox("option", "boxManager").addMsg(id, msg);
 }
 });
 }
 });
 });
</script>