diff --git a/htdocs/core/js/lib_notification.js.php b/htdocs/core/js/lib_notification.js.php
index cb8a80bbd78..04b325c3ab8 100644
--- a/htdocs/core/js/lib_notification.js.php
+++ b/htdocs/core/js/lib_notification.js.php
@@ -1,6 +1,7 @@
 <?php
 /* Copyright (C) 2016	   Sergio Sanchis		<sergiosanchis@hotmail.com>
  * Copyright (C) 2017	   Juanjo Menent		<jmenent@2byte.es>
+ * Copyright (C) 2020	   Destailleur Laurent  <eldy@users.sourceforge.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -35,26 +36,9 @@ if (! ($_SERVER['HTTP_REFERER'] === $dolibarr_main_url_root . '/' || $_SERVER['H
 
     top_httphead('text/javascript; charset=UTF-8');
 
-    $nowtime = time();
-    //$nowtimeprevious = floor($nowtime / 60) * 60;   // auto_check_events_not_before is rounded to previous minute
-
-    // TODO Try to make a solution with only a javascript timer that is easier. Difficulty is to avoid notification twice when.
-    /* session already started into main
-    session_cache_limiter('public');
-    header('Cache-Control: no-cache');
-    session_set_cookie_params(0, '/', null, false, true);   // Add tag httponly on session cookie
-    session_start();*/
-    if (! isset($_SESSION['auto_check_events_not_before']))
-    {
-        print 'console.log("_SESSION[auto_check_events_not_before] is not set");'."\n";
-        // Round to eliminate the seconds
-        $_SESSION['auto_check_events_not_before'] = $nowtime;
-    }
-    print 'var nowtime = ' . $nowtime . ';' . "\n";
     print 'var login = \'' . $_SESSION['dol_login'] . '\';' . "\n";
-    print 'var auto_check_events_not_before = '.$_SESSION['auto_check_events_not_before']. ';'."\n";
-    print 'var time_js_next_test = Math.max(nowtime, auto_check_events_not_before);'."\n";
     print 'var time_auto_update = '.$conf->global->MAIN_BROWSER_NOTIFICATION_FREQUENCY.';'."\n";   // Always defined
+    print 'var time_js_next_test = (Date.now() + time_auto_update);'."\n";
     ?>
 
 	/* Check if permission ok */
@@ -66,7 +50,7 @@ if (! ($_SERVER['HTTP_REFERER'] === $dolibarr_main_url_root . '/' || $_SERVER['H
    	// We set a delay before launching first test so next check will arrive after the time_auto_update compared to previous one.
     var time_first_execution = (time_auto_update - (nowtime - time_js_next_test)) * 1000;	//need milliseconds
     if (login != '') {
-    	console.log("Launch browser notif check: setTimeout is set to launch 'first_execution' function after a wait of time_first_execution="+time_first_execution+". nowtime (time php page generation) = "+nowtime+" auto_check_events_not_before (val in session)= "+auto_check_events_not_before+" time_js_next_test (max now,auto_check_events_not_before) = "+time_js_next_test+" time_auto_update="+time_auto_update);
+    	console.log("Launch browser notif check: setTimeout is set to launch 'first_execution' function after a wait of time_first_execution="+time_first_execution+". nowtime (time php page generation) = "+nowtime+" time_js_next_test = "+time_js_next_test+" time_auto_update="+time_auto_update);
     	setTimeout(first_execution, time_first_execution);
     } //first run auto check