var sendReq = getXmlHttpRequestObject();
var receiveReq = getXmlHttpRequestObject();
var lastMessage = 0;
var mTimer;

// Inicia o servidor de Chat
function startChat() {
	document.getElementById('txt_message').focus();
	getChatText();
}		
// Inicia objetos Ajax
function getXmlHttpRequestObject() {
	if (window.XMLHttpRequest) {
		return new XMLHttpRequest();
	} else if(window.ActiveXObject) {
		return new ActiveXObject("Microsoft.XMLHTTP");
	} else {
		document.getElementById('p_status').innerHTML = 'Imcompativel';
	}
}
//recebe gravação e chama função para escrever

// função para gravação
function handleSendChat() {
	clearInterval(mTimer);
	getChatText();
}

//Função de alerta de novo evento
function alerta(){
	document.getElementById('body').focus();
	document.getElementById('txt_message').focus();	
	document.getElementById('som').src = "som/receive.mp3";
}
// Escreve o texto atualizado
function handleReceiveChat() {
	if (receiveReq.readyState == 4) {
		var chat_div = document.getElementById('div_chat');
		var xmldoc = receiveReq.responseXML;
		var message_nodes = xmldoc.getElementsByTagName("menssage"); 
		var n_messages = message_nodes.length
		for (i = 0; i < n_messages; i++) {
			alerta();
			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 += '<b>' + user_node[0].firstChild.nodeValue + '</b>' + '&nbsp;';
			chat_div.innerHTML += '<font size="1">' + time_node[0].firstChild.nodeValue + '</font><br />';
			chat_div.innerHTML += '&nbsp;&nbsp;&nbsp;' + text_node[0].firstChild.nodeValue + '<br />';
			chat_div.scrollTop = chat_div.scrollHeight;
			lastMessage = (message_nodes[i].getAttribute('id'));
		}
		mTimer = setTimeout('getChatText();',2000); 
	}
}
// faz formulario retornar...
function blockSubmit() {
	sendChatText();
	return false;
}