function createXMLHTTP(){
	var ajax;
	try {
		ajax = new ActiveXObject("Microsoft.XMLHTTP");
	}  catch(e){
		try {
			ajax = new ActiveXObject("Msxml2.XMLHTTP");
			alert(ajax);
		} catch(ex) {
			try {
				ajax = new XMLHttpRequest();
			} catch(exc) {
				alert("Esse browser não tem recursos para uso do Ajax");
				ajax = null;
			}
		}
		return ajax;
	}

	var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
	"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
	"Microsoft.XMLHTTP"];
	
	for (var i=0; i < arrSignatures.length; i++) {
		try {
			var oRequest = new ActiveXObject(arrSignatures[i]);
			return oRequest;
		} catch (oError) {}
	}

	throw new Error("MSXML is not installed on your system.");
}


function enviaAjax(envio, divretorno, pagina){	
	
	var oHTTPRequest = createXMLHTTP(); 
	oHTTPRequest.open("post", pagina, true); 
	oHTTPRequest.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	oHTTPRequest.setRequestHeader("Encoding", "UTF-8");
	oHTTPRequest.onreadystatechange = function() {
		if (oHTTPRequest.readyState==4) {
			if(oHTTPRequest.status == 200){
				if(document.getElementById(divretorno)){
					document.getElementById(divretorno).innerHTML = oHTTPRequest.responseText; 
				}
			} else {
				//alert(oHTTPRequest.responseText);	
				//alert(divretorno);  
			}
		}
	}
	oHTTPRequest.send(envio);
}