JSON,JSP,AJAX - comment traiter les donnees

response.getWriter().println(buffer);

var recu =xmlHttp.responseText;

if(window.XMLHttpRequest) // Firefox
   xhr_object = new XMLHttpRequest();
else if(window.ActiveXObject) // Internet Explorer
   xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
else { // XMLHttpRequest non supporté par le navigateur
     alert("Votre navigateur ne supporte pas les objets XMLHTTPRequest...");
     return;
     }
fic = "ta_page.jsp"
xhr_object.open("POST", fic, true);

xhr_object.onreadystatechange = function()
  {
  if (xhr_object.readyState == 4)
     {
	 v = xhr_object.responseText
	 if (v.length > 0)
	    {
           alert(v)
	    
	    }
     }
  }
xhr_object.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
var data = "nom="+n+"&prenom="+p // variables passées à jsp
xhr_object.send(data);