function createRequest() 
{
    var request = false;
    try 
    {
        request = new XMLHttpRequest();
    } catch (trymicrosoft) 
    {
        try 
        {
            request = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (othermicrosoft) 
        {
            try 
            {
                request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (failed) 
            {
                request = false;
            }
        }
    }

    if (!request) 
    {
        alert("Error to initial XMLHttpRequest object, so you cannot " + 
              "use AJAX to validate what you inputed!");
    } else 
    {
        return request;
    }
}