Liste des popups ouvert

var w;
window.addEventListener("message", function receiveMessage(event) {log(event.data) ;});
window.onload = function () { if (w) w.postMessage("said hello","*");};
window.onbeforeunload = function () { if (w) w.postMessage("said goodbye","*");};
function log(message){
  document.getElementById("data").innerHTML += message + "<br>";}

 if (w)

w=window.open(page,nom_popup,"menubar=no, status=yes, scrollbars=yes, menubar=no, width=800, height=400, resizable");