JavaScript : approche Ajax...

var rq = false;
try {
  rq = new XMLHttpRequest();
} catch (trymicrosoft) {
  try {
    rq = new ActiveXObject("Msxml2.XMLHTTP");
  } catch (othermicrosoft) {
    try {
      rq = new ActiveXObject("Microsoft.XMLHTTP");
    } catch (failed) {
      rq = false;
    }
  }
}
function getSource() {
  var urlBrute = document.getElementById("sujet").value;
  // alert("URL brute: " + urlBrute);
  // var url = escape(urlBrute);
  // alert("url: " + url);
  rq.open("GET", urlBrute, true);
  rq.onreadystatechange = function () {
    // alert("Changement d'etat sur reception: " + rq.readyState);
    document.getElementById("progression").value = "Etape " + rq.readyState;
    if (rq.readyState == 4) {
      if (rq.status == 200 || rq.status == 0) {
        var rep = rq.responseText;
        // alert("Etat: " + rq.status + "; contenu: " + rep);
        document.getElementById("resultats").value = rep;
        document.getElementById("progression").value = "Termine";
      } else if (rq.status == 404) {
        alert("Erreur sur l'URL demandee: " + rq.url);
      } else {
        alert("Erreur: code " + rq.status);
      }
    }
  }
  rq.send(null);
}