var req;
function loadXMLDoc(url){

	req = null;
	if (window.XMLHttpRequest) {
 
 		req = new XMLHttpRequest();
 		req.onreadystatechange = processReqChange;
		req.open("GET", url, true); 
 		req.send(null);

	} else if (window.ActiveXObject) {
		try {
			req = new ActiveXObject("Msxml2.XMLHTTP.4.0");
		} catch(e) {
			try {
				req = new ActiveXObject("Msxml2.XMLHTTP.3.0");
			} catch(e) {
				try {
					req = new ActiveXObject("Msxml2.XMLHTTP");
				} catch(e) {
					try {
						req = new ActiveXObject("Microsoft.XMLHTTP");
					} catch(e) {
						req = false;
					}
				}
			}
		}

		if (req) {
		 	req.onreadystatechange = processReqChange;
 			req.open("GET", url, true);
			req.send();
		}
	}
	
}
/*
function loadXMLDoc(url)
{
	req = null;
	// Procura por um objeto nativo (Mozilla/Safari)
	if (window.XMLHttpRequest)
	{
		req = new XMLHttpRequest();
		req.onreadystatechange = processReqChange;
		req.open("GET",url,true);
		req.send(null);
	}
	// Procura por uma versão ActiveX (IE)
	else if (window.ActiveXObject)
	{
		req = new ActiveXObject("Microsoft.XMLHTTP");
		if (req)
		{
			req.onreadystatechange = processReqChange;
			req.open("GET",url,true);
			req.send();
		}
	}
}
*/

function processReqChange(){

	if (req.readyState == 4) {
		if (req.status == 200) {
			document.getElementById("retorno").innerHTML = req.responseText;
		} else {
			alert("Houve um problema ao obter os dados:\n" + req.statusText);
		}
	}
	
}



function atualiza(valor){
	document.getElementById("retorno").innerHTML = "<img src='cep/loading.gif' >";
	loadXMLDoc("cep/cep.php?id="+valor);
}