var request = null;

function GetRequest(){

    if(window.XMLHttpRequest){
        try{
            request = new XMLHttpRequest();
        }catch(e){

        }
    }else if(window.ActiveXObject){
        try{
            request = new ActiveXObject('Msxml2.XMLHTTP');
        }catch(e){
            try{
                request = new ActiveXObject('Microsoft.XMLHTTP');
            }
            catch(e){}
        }
    }
    return request;
}

function BeginRequest(verb, url, message, callback){
    request = GetRequest();
    if(!request){
        alert('Could not create XMLHttpRequest');
        return;
    }

    request.open(verb, url, true); // открытие запроса
      if(verb == 'POST')
        request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded'); // только для POST запросов

    request.onreadystatechange = callback; // callback функция
    request.send(message);
    
}