Is it possible to read a session value with Javascript?
For example, if I assigned a value into a session in PHP:
$_SESSION['msg'] = "ABC Message";
Is it possible to read $_SESSION['msg'] with Javascript?
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7 Answers
A very simple way is to generate the JavaScript with some PHP code:
<script type="text/javascript">
<?php echo 'var msg = "'.json_encode($_SESSION['msg']).'";';
</script>
4 Comments
Jeff Ober
If $_SESSION['msg'] stores sensitive information, outputting to an unencrypted page is a security risk, and HTTPS should be used.
svassr
but by doing so you expose the value directly and it's accessible from the console and can be modified. What if you need to get a sensible information like a privilege_type id and you don't want your user to be able to change it : you need to access such value at runtime from a private methode and never store it to use it later.
Nurgiel
If this gets cached then you'll see your world burn. That's why I prefer cookie method which is accepted answer.
suchislife
Wow. There's a good answer and 2 good constructive points. My question based on this specific answer and these comments is, what if I just want to check if the user is in fact logged in? Just a quick true or false check returned in JSON as presented in this reply, regarding a successful login that has already happen in a different page written in PHP Only? Then it's OK?
$_SESSION is a server-side construct. You would need to store that variable in $_COOKIE to be able to access it client-side.
7 Comments
da5id
Why is this being voted up? harto's solution proves it untrue.
da5id
Yes agreed, but it doesn't answer the question and is in fact presenting misleading information.
Will Green
How is this misleading? You cannot read a session variable with javascript. You either have to stuff the value into a cookie, which javascript could access, or have it rendered out to the page itself. That is not very secure.
Danny Tuppeny
Cookies are no more secure, they're easily visible in most browsers.
Will Green
Right. Shouldn't have mentioned security. My point was that $_SESSION is not a client-side construct. Either stash the value in a client-side construct ($_COOKIE, render it out in the HTML), or make an AJAX request to a service that will return that value from your server-side session.
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.. Or you can use ajax to retrive your server side session value into you client-side javascript.` (quick, dirty and untested example, using jQuery)
Javascript Side:
$.ajax({
url: "test.php",
cache: false,
success: function(html){
eval( html ); /// UGLY NASTY YOU MUST VALIDATE YOUR INPUTS... JUST AN EXAMPLE
}
});
PHP side test.php:
echo 'var myData = "'. $_SESSION['msg'].'"';
Comments
If this helps anyone, those examples returned null, so I just used:
<?php session_start();
$msg = $_SESSION['msg'];
?>
<script>
<?php echo "var msg = '" .$msg . "'"; ?>
</script>
3 Comments
MaGnetas
Not really answering the question
user2954658
I see you -1'd me. The question is "Is it possible to read $_SESSION['msg'] with Javascript?" my answer uses javascript to access a php variable, in case that helped anyone. Your comment is that my answer did not resolve the question. You are wrong.
MaGnetas
Read your answer once again. The question was is it possible to read session variables. The answer is "No", but there's a workaround helpful in some situations. You didn't state that. Also some code formatting would be nice. var msg = '<?php echo $msg; ?>'; looks much better than joining the whole javascript line in php. I'm sorry, but this doesn't look like the answer to the question asked. Try improving it.
To make an even easier example of Luis Melgratti´s answer you can just return a json encoded value from PHP and use jQuery to parse it, like this:
Javascript:
$("#some_button")
.click(function()
{
$.ajax(
{
url: "get_session.php",
cache: false
})
.done(function(result)
{
var session_credentials = $.parseJSON(result);
console.log(session_credentials);
});
});
PHP:
//get_session.php
<?php
session_start();
echo json_encode($_SESSION);
?>
I believe there are even more answers on a similar SO-thread here: how-to-access-php-session-variables-from-jquery-function-in-a-js-file
Comments
May It Works :
function getCookie(name) {
var value = "; " + document.cookie;
var parts = value.split("; " + name + "=");
if (parts.length == 2) return parts.pop().split(";").shift();
}
getCookie('PHPSESSID');
