if(typeof XMLHttpRequest == 'undefined'){//AJAX
  alert("your browser does not support the XMLHttpRequest object. this software WILL NOT WORK");
 }

function subscribe(addr)
{
    request = new XMLHttpRequest();
    var url = '/ajax/list_subscribe.php?email_subscribe_addr=' + addr;

    request.open("GET", url, false);
    request.send();
  
  if(request.status == 200){
    var response = request.responseXML;
    if(response && response.documentElement){
      var response_status = response.getElementsByTagName('status')[0].firstChild.data;
      var response_message = response.getElementsByTagName('message')[0].firstChild.data;	
        alert(response_message);
        return response_status;
    }else{
      alert("The server encountered an unknown error.");
    }
  }else{
    alert("The server didn't respond.");
  }
  return false;
}
function unsubscribe(addr)
{
    //alert('unsubscribe ' + addr);
}