function handleHttpResponse() {
	if (http.readyState == 4) {
		if (http.status == 200) {
			if (http.responseText.indexOf('invalid') == -1) {
				results = http.responseText.split(";");
				//document.getElementById("max_price").innerHTML = results[0];
				document.getElementById("max_price").value = results[0];
				emProcesso = false;
			}
		}
	}
}

function verificaUtilizador(num) {
	if (!emProcesso && http) {
		//var valor = escape(document.getElementById("cod_artigo").value);
		var valor = num;
		//alert(valor);
		var url = "teste.php?txtUser="+ valor;
		http.open("GET", url, true);
		http.onreadystatechange = handleHttpResponse;
		emProcesso = true;
		http.send(null);
	}
}

/*function getHTTPObject() {
	var xmlhttp;

	if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {
		try {
			xmlhttp=new XMLHttpRequest();
		} catch (e) { xmlhttp=false; }
	}
	
	if (!xmlhttp && window.createRequest) {
		try {
			xmlhttp = window.createRequest();
		} catch (e) {
			xmlhttp=false;
		}
	}
	
	return xmlhttp;
}*/

function getHTTPObject() {
var req;

	try {
		if (window.XMLHttpRequest) {
			req = new XMLHttpRequest();

			if (req.readyState == null) {
				req.readyState = 1;
				req.addEventListener("load", function () {
					req.readyState = 4;

					if (typeof req.onReadyStateChange == "function")
						req.onReadyStateChange();
				}, false);
			}

			return req;
		}

		if (window.ActiveXObject) {
			var prefixes = ["MSXML2", "Microsoft", "MSXML", "MSXML3"];

			for (var i = 0; i < prefixes.length; i++) {
				try {
					req = new ActiveXObject(prefixes[i] + ".XmlHttp");
					return req;
				} catch (ex) {};
			}
		}
	} catch (ex) {}

	alert("XmlHttp Objects not supported by client browser");
}

var emProcesso = false;
var http = getHTTPObject();