如何在PHP中的$ _SESSION中保存值并检索

Question

I want to show the usermail once I login and the page after login should show "Welcome alex01@gmail.com" my login page php code is

<?php
if(isset($_POST['submit']))
{
    $host="localhost";
    $user="root";
    $pass="";
    $db="documentation";
    $usermail=$_POST['email'];
    $password=$_POST['password'];

    $conn=mysqli_connect($host,$user,$pass,$db);
    $query="SELECT * FROM users where
    user_mail='$usermail' and password='$password'";
    $result=mysqli_query($conn,$query);
    if(mysqli_num_rows($result)==1)
    {
        session_start();
        $_SESSION['documentation']='true';
        $_SESSION['user_mail']=$_POST['email'];
        header('location:index.php');
    }
    else{echo 'wrong username or password';}

}
?>

The code of my index.php (the page user see after login)

<?php
session_start();
$_SESSION['user_mail']=$_POST['email'];
if(!$_SESSION['documentation'])
{
    header('location:login.php');
}
?>

I am trying to save the usermail by

$_SESSION['user_mail']=$_POST['email'];

and I am trying to retrieve the value in index.php by writing

$_SESSION['user_mail']=$_POST['email'];

but it is not showing the user name

Answer 1

In your index.php page retrive like this;

 $usermail = $_SESSION['user_mail']; 
 echo $usermail;

Answer 2

通过echo $_SESSION['user_mail'];检索会话echo $_SESSION['user_mail'];

Answer 3

to display session data, just write

echo $_SESSION['user_mail'];

Also ensure to start session on page where session is used.

Answer 4

You are overwriting the value of $_SESSION['user_mail] in index page with $_POST['email]. The problem is that $_POST['email'] is not set on index page, its only set on the login page.

So on index.php page you simply have to either

echo $_SESSION['user_mail'];

or

$var = $_SESSION['user_mail']; echo $var;

Answer 5

For save in session variable:-

$usermail = $_SESSION['user_mail'];

and for show in same page .

echo $usermail;

in other page :-

//first start session
session_start();
echo $_SESSION["username"];
//or 
session_start();
$loginname=$_SESSION["username"];
echo $loginname;

Please, make sure the session is started on the page where session is being used.