function analyse() {
  var arrivee = document.getElementById("date_arrivee").value;
  var depart = document.getElementById("date_depart").value;
  var gite = document.getElementById("gite").value;
  
  createRequestObject();
  
  document.getElementById('resultat').innerHTML = '<img src="../img/chargement.gif" alt="Chargement..." />';
  http = createRequestObject();
  http.open('post', 'rechercheDispo.php', true);
  http.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); 
  http.send("gite="+gite+"&debut="+arrivee+"&fin="+depart);
  http.onreadystatechange = handleAJAXReturn;
  
 }
  
function handleAJAXReturn()
{
    if(http.readyState == 4)
    {
        if(http.status == 200)
        {
             document.getElementById('resultat').innerHTML = http.responseText;
        }
        else
        {
             document.getElementById('resultat').innerHTML = "<b>N/A</b>";
        }
    }
}
  
function createRequestObject()
{
    var http;
    if(window.XMLHttpRequest)
    { // Mozilla, Safari, ...
        http = new XMLHttpRequest();
    }
    else if(window.ActiveXObject)
    { // Internet Explorer
        http = new ActiveXObject("Microsoft.XMLHTTP");
    }
    return http;
}