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.");
	}