function request(url, postdata, async, method){

  var http = new XMLHttpRequest();
  var query;

  http.open(method, url, async);
  //Send the proper header information along with the request
  http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

  http.onreadystatechange = function() {//Call a function when the state changes.

    if(http.readyState == 4 && http.status == 200){
      console.log("successfully request \nURL:"+url+"\n STATUS:"+http.status+"\nPOST:"+postdata+"\nAnswer:"+http.responseText)
      query = http.responseText;
    }
    else if(http.readyState == 4 && http.status >= 400 || http.status >= 300){
      console.log("send request error or network error \nURL:"+url+"\nPOST:"+postdata+"\nAnswer:"+http.responseText)
      return request(url, postdata, async, method);
    }
  }

    http.send(postdata);

  return query;
}