Session

Même réponse que sur codes sources... sabs voir ton code impossible de t'aider.

<form action="trauthdirectrice.php" method="POST">

<table border="7" bgcolor="lightblue">
<tr><td><input type="text" name="" value="المديرة" disabled="disabled"></TD><TD><B><center> : مصلحة </B></TD></TR>
<tr><td><input type="text" name="directrice" value="المديرة" hidden></TD></TR>
<tr><td><input type="password" name="password" required required onKeypress="
if (event.keyCode==61 || event.keyCode==39 || event.keyCode==92 || event.keyCode==34 || event.keyCode==60 || event.keyCode==63 ) event.returnValue = false;
if (event.which==61 || event.which==39 || event.keyCode==92 || event.keyCode==34 || event.keyCode==60 || event.keyCode==63 ) return false;"></td><td><font color="red"><B><center> : كلمة المرور </center></font> </td></tr>

<tr><td><input type="submit" name="submit" value=" تسجيل الدخول "></td>
<td><input type="reset" value=" مسح "></td></tr>
</table>

</form>
<?php
SESSION_START();
$directrice = $_POST['directrice'];
$passe = $_POST['password'];
?>
<?php
include ("bdd.php");

$reponse=$bdd->query('SELECT * FROM tdirectrice WHERE SERVICE=\''.$directrice.'\' AND PASSE=\''.$_POST['password'].'\' ');
$donnees=$reponse->fetch();
if(empty($_POST['directrice']) || (empty($_POST['password'])))

{

}
else if($donnees['PASSE']==($_POST['password'])){

$_SESSION['DIRECTRICE'] = $_POST['directrice'];

header('location:acceuildirectrice.php');

}
else {

header('location: index.html');
}

?>
<html>
<?php
SESSION_START();
?>
<html>
<head>
<meta charset="UTF-8">
<link rel="stylesheet" type="text/css" href="styleformservice.css">
</head>
<?php
include("enteteimgdefault.php");
include("entetemenudirectrice.php");
?>
<BR>
<table border="1" bgcolor="lightblue"align="right">

<tr>

<td><input type="text" value="<?php echo $_SESSION["DIRECTRICE"]; ?>" disabled="disabled" align="right"></td>
<td><b>  :  المصلحة المتصلة </b></td>
</tr>
</table>
<br><br><br>
<?php
include("annoncespardirectrice.php");

?>
pour ce utilisateur ca marche bien mais quand j'ouvre un nouveau onglet et je fais l'authentification pour un autre utilisateur deferent sa pose le probleme

Sujet traité dans la question initiale :
https://codes-sources.commentcamarche.net/forum/affich-10087808-seession-en-php#4

je mets cette discussion en résolue.