function Requete(variable, action, zone)
{
 var xhr_object = null; 

 if (window.XMLHttpRequest)
 {xhr_object = new XMLHttpRequest();}
 else if (window.ActiveXObject)
 {xhr_object = new ActiveXObject("Microsoft.XMLHTTP");}
 else
 {
  alert("Erreur : utilisez Firefox ou Internet Explorer");
  return;
 } 

 switch (action)
 {
 case 0:
  xhr_object.open("GET", variable, true);
  break;

 case 1:
  xhr_object.open("POST",'http://www.insiderz.fr/old_concours.php', true);
  break;
 }

  xhr_object.onreadystatechange = function()
  {
    if(xhr_object.readyState==4)
    {
      var tempobj = document.getElementById(zone);
      tempobj.innerHTML=xhr_object.responseText;
    }
  }

  if(action==1)
  {
    xhr_object.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    xhr_object.send(variable);
  }
  else
  {xhr_object.send(null);}
}

function comment()
{
  var text = document.comm.text.value;
  var id_rea = document.comm.id_rea.value;
  Requete('a=add&text='+text+'&id_rea='+id_rea, 1, 'zone_comm');
}