How to read php session values inside javascript?

Question

i am very new in html ,JS and php . I have created a page that has only a sidebare menu with some options and there are some users logged in(in the log in phase i used php with mySQL for my base in an other file):

    <div id="mySidenav" class="sidenav">
    <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
    <a id="concerts"href="#">Concerts</a>
    <a id="favorites"href="#">Favorites</a>
    <a id="organizer"href="#">Orginizer</a>
    <a id="admin"href="#">Administration</a>
</div>


<span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; </span>

<script>
    function openNav() {
        document.getElementById("mySidenav").style.width = "250px";
    }

    function closeNav() {
        document.getElementById("mySidenav").style.width = "0";
    }

    document.getElementById("concerts").onclick = function () {
        location.href = "concerts.php";
    };

My problem here is that i need to exclude some users lets say based on their names by clicking on the 'Concerts' option from my menu . How can i do that in javascript ?

i thought of php SESSION but nothing seems to work .

Any help would be valuable and i am really sorry if the answer is too obvious.

The idea of the session values is to keep the secrets in the server, they should not be exposed outside of the server. — Teemu
– Teemu, Commented Nov 30, 2021 at 16:39

tyazeez · Accepted Answer · 2021-11-30 18:06:53Z

1

I have modified your original code a bit. I added a PHP code to show you how to determine the registration status of your users using their name. Then I modified the JS to show you how to get and use the registration status to allow or deny access to your concert page.

Consider improving your code by: 1)Using session variable to hold the user name. 2)Query your DB for registered users and populate it into an array. 3)Instead of using name as a criteria for screening consider using their id.

<?php
   
//session_start();
//$name = $_SESSION['name'];

// Create 2 variables $name and $registered_names
$name = 'Jane';
$registered_names = ['John', 'Rose', 'Steve', 'James', 'Jane'];

// Check if name of current user is among the array of registered names 
$is_registered = is_int(array_search($name, $registered_names));

?>

<div id="mySidenav" class="sidenav">
    <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
    <a id="concerts" href="#">Concerts</a>
    <a id="favorites" href="#">Favorites</a>
    <a id="organizer" href="#">Orginizer</a>
    <a id="admin" href="#">Administration</a>
</div>

<span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; </span>

<!----------Attach the registration status to an hidden input field-------->
<input id="registration-status" type="hidden" value="<?php echo $is_registered ?>">

<script>
const
    is_registered = document.getElementById('registration-status').value

function openNav() {
    document.getElementById("mySidenav").style.width = "250px";
}

function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
}

document.getElementById("concerts").onclick = function() {
    // Finally check the registration status before giving them access
    if (is_registered) {
        location.href = "concerts.php";
    }
};
</script>

edited Nov 30, 2021 at 18:06

answered Nov 30, 2021 at 17:53

tyazeez

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2 Comments

Γιάννης Γιαννάκος Over a year ago

Perfect . Thank you so much .

tyazeez Over a year ago

You're most welcome, glad it worked :)

Story · Accepted Answer · 2021-11-30 18:45:54Z

1

It's a bad practice to use client side(JS) to restrict access to a resource. Because any users can modify JS code and modify/bypass your logic.

PHP session is a good thing to authenticate and manage which part of your front-end users will access or not.

You can use session_start() at the top of the php files to check if users are logged or not.

[EDIT] To restrict user from accessing somehting,you can use something like PHP manual :

if ( isset( $_SESSION['user'] ) ) {
// restricted to login user
}

edited Nov 30, 2021 at 18:45

answered Nov 30, 2021 at 16:48

Story

591 silver badge4 bronze badges

1 Comment

Γιάννης Γιαννάκος Over a year ago

User is connected ,but i want to restrict him form accessing the concerts.php file

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