var req;


function loadXMLDoc(url,tipo) {
	numrand = Math.ceil(Math.random()*1000);
	url = url + "?rnd=" + numrand;
    // branch for native XMLHttpRequest object

    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
		req.open("POST", url, true);
		req.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
		req.send(tipo);
    // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        isIE = true;
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
            req.onreadystatechange = processReqChange;
		req.open("POST", url, true);
		req.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
		req.send(tipo);
        }
    }
}