function refresh_properties()
{
    if (ready_to_accept())
    {
        xmlHttp.open('GET', '/ajax_commands/refresh_properties.php');
        xmlHttp.onreadystatechange = function myFunction()
        {
            if (ready_to_process())
            {
                aProperties = xmlHttp.responseText.split('**');
                
                for (a = 0; a < aProperties.length; a++)
                {
                    document.getElementById('property_' + a).innerHTML = aProperties[a];
                }
                setTimeout('refresh_properties()', (30*1000));
            }
        }
        xmlHttp.send(null);
    }
    else
    {
        setTimeout('refresh_properties()', 250);
    }
}