AJAX chat script - not returning values?

[opalelement]

I am trying to get this chat script to work (from a tutorial here)

 

My current code:

<?php
if(!isset($_GET['mode']))
{
echo <<<REGION
<script type="text/javascript">
var sendReq = getXmlHttpRequestObject();
var receiveReq = getXmlHttpRequestObject();
var lastMessage = 0;
var mTimer;

function getChatText() {
if (receiveReq.readyState == 4 || receiveReq.readyState == 0) {
	receiveReq.open("GET", 'chat.php?action=chat&mode=get&last=' + lastMessage, true);
	receiveReq.onreadystatechange = handleReceiveChat; 
	receiveReq.send(null);
}			
}

function getXmlHttpRequestObject() {
if (window.XMLHttpRequest) {
	return new XMLHttpRequest();
} else if(window.ActiveXObject) {
	return new ActiveXObject("Microsoft.XMLHTTP");
} else {
	document.getElementById('chat_status').innerHTML = 
	'Status: Cound not create XmlHttpRequest Object. Consider upgrading your browser.';
}
}

function handleReceiveChat() {
if (receiveReq.readyState == 4) {
	var chat_div = document.getElementById('div_chat');
	var xmldoc = receiveReq.responseXML;
	var message_nodes = xmldoc.getElementsByTagName("message"); 
	var n_messages = message_nodes.length
	for (i = 0; i < n_messages; i++) {
		var user_node = message_nodes[i].getElementsByTagName("user");
		var text_node = message_nodes[i].getElementsByTagName("text");
		var time_node = message_nodes[i].getElementsByTagName("time");
		chat_div.innerHTML += user_node[0].firstChild.nodeValue + ' ';
		chat_div.innerHTML += '<font class="chat_time">' 
		chat_div.innerHTML += time_node[0].firstChild.nodeValue + '</font><br />';
		chat_div.innerHTML += text_node[0].firstChild.nodeValue + '<br />';
		lastMessage = (message_nodes[i].getAttribute('id'));
	}
	mTimer = setTimeout('getChatText();',2000);
}
}

function sendChatText() {
if (sendReq.readyState == 4 || sendReq.readyState == 0) {
	sendReq.open("POST", 'chat.php?action=chat&mode=send', true);
	sendReq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
	sendReq.onreadystatechange = handleSendChat; 
	var param = 'message=' + document.getElementById('txt_message').value;
	//param += '&name=Ryan Smith';
	//param += '&chat=1';
	sendReq.send(param);
	document.getElementById('txt_message').value = '';
}							
}

function handleSendChat() {
//Clear out the existing timer so we don't have 
//multiple timer instances running.
clearInterval(mTimer);
getChatText();
}
</script>

	<h2>AJAX Driven Web Chat.</h2>
	<p id="p_status">Status: Normal</p>
	Current Chitter-Chatter:
	<div id="div_chat" class="chat_main" style="border:solid 1px;background-color: #DDCCAA; margin-left: 2px;padding:3px;">

	</div>
	<form id="frmmain" name="frmmain" onsubmit="">
		<input type="button" name="btn_get_chat" id="btn_get_chat" value="Refresh Chat" onclick="javascript:getChatText();" />
		<input type="button" name="btn_reset_chat" id="btn_reset_chat" value="Reset Chat" onclick="javascript:resetChat();" /><br />
		<input type="text" id="txt_message" name="txt_message" style="width: 447px;" />
		<input type="button" name="btn_send_chat" id="btn_send_chat" value="Send" onclick="javascript:sendChatText();" />
	</form>
REGION;
}
else
{
if($_GET['mode'] == "get")
{
	$header_auth = true;
	include("validate.php"); // Validates the login
	echo <<<REGION
	<?xml version="1.0" ?><root>
	<message id="0">
	<user>Admin</user>
	<text>Welcome</text>
	<time>12:00</time>
	</message>
	</root>
REGION;

}
else if($_GET['mode'] == "send")
{

}
}

?>

 

The output of directly accessing the chat.php?action=chat&mode=get&last=0:

		<root> 
	<message id="0"> 
	<user>Admin</user> 
	<text>Your are not currently in a chat session.</text> 
	<time>7:30</time> 
	</message> 
	</root>

 

I don't understand why it is not returning the chat... Can someone help me?

 

[jacksonmj]

The tutorial code seems to expect a "chat=[number]" in the URL when sending or receiving messages - so perhaps you should try something like:

 

chat.php?action=chat&mode=get&last=0&chat=1