function ajaxInit() {
var req;

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

return req;
}

function set_xmlhttp() {
    try {
      xmlhttp = new XMLHttpRequest();
    } catch (e) {
      try {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
        try {
          xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {
          xmlhttp = false;
        }
      }
    }
}