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I'm trying to pass the a variable from JavaScript to PHP using AJAX, but I'm unable to do so. Whenever I try to var_dump($_POST['winner_id']) it returns NULL. I've tried to check the AJAX call with Developer Tools in Chrome and it showed winner_id:0 - which is right.

Here is my code:

JavaScript

 function ajaxCall() {

   alert("To AJAX: the winnerid is: "+winner_id);

        $.ajax
        (   {


                type: "POST",
                url: "ajax.php",
                data: {winner_id : winner_id}, 
                success: function(response)
                { alert("The winner was passed!")}
            }
        );
};
ajaxCall();

PHP Code

<?php 
session_start();

if(isset($_POST['winner_id']))

{
    $winner_id = $_POST['winner_id']."";
    var_dump($winner_id);
}

var_dump($_POST['winner_id']);

?>

If I do a var_dump($_POST) in the beginning of the PHP script then it gives me array(0) { }

I'm new to web development and have been trying to figure this out for hours now. Any hints would be much appreciated. Thanks!

share|improve this question
Uhm, if you're passing an actual zero to PHP, what are you expecting back. Did you try this with some easily identifiable strings instead ? – adeneo Apr 29 at 3:44
Does success get called? – Explosion Pills Apr 29 at 3:45
I initiate and calculate the winner_id before I call the ajax function and use the winner_id inside it – user2330619 Apr 29 at 3:45
what is the possible values for winner_id in $.ajax data..? – Dipesh Parmar Apr 29 at 3:45
yes, success gets called – user2330619 Apr 29 at 3:46
show 3 more comments

3 Answers

up vote 2 down vote

Where are you intializing the winner_id.Either you have to pas it as an argument or intitialize it as aglobal variable.

function ajaxCall(winner_id) {

   alert("To AJAX: the winnerid is: "+winner_id);

        $.ajax
        ({
                type: "POST",
                url: "ajax.php",
                data: {"winner_id" : winner_id}, 
                success: function(response)
                  { 
                     alert("The winner was passed!");
                  }
        });
};
ajaxCall(winner_id);
share|improve this answer
Thank you Deepu! I followed the instructions you gave me, made sure that I pass in the winner_id as the argument for the function and I can see that it passes the result, however I'm still unable to get the winner_id in my php code var_dump($_POST['winner_id'])= NULL – user2330619 Apr 29 at 4:52
up vote 0 down vote

Where did you initiate value to winner_id? like

function ajaxCall() {
var winner_id = '123';
...

or if you initiated winner_id before calling ajaxCall() ,you should call ajaxCall() with parameters like ajaxCall($winnerid), which $winnerid is from your PHP and then

function ajaxCall(winner_id) {
...
share|improve this answer
I tried to input the winner_id as a parameter for the ajax function and success was called, also as I went into the developer tools / network and XHR, it showed that the winner_id = 1 (which was right) – user2330619 Apr 29 at 4:04
so if i suppose your initiated value is $winnerid just call function like ajaxCall($winnerid). – Amir Apr 29 at 4:05
so what is the problem? – Amir Apr 29 at 4:12
Thank you Amir, the problem is that I'm still unable to get the winner_id in my php code: var_dump($_POST['winner_id'])= NULL – user2330619 Apr 29 at 4:53
are you sure, your PHP code is in ajax.php at the same folder? – Amir Apr 29 at 4:58
show 1 more comment
up vote 0 down vote

i guess you have to convert your winner_id to a string because php read zero (0) as null

function ajaxCall() {

   alert("To AJAX: the winnerid is: "+winner_id);

        $.ajax
        (   {


                type: "POST",
                url: "ajax.php",
                data: {winner_id : winner_id.toString()}, 
                success: function(response)
                { alert("The winner was passed!")},
                dataType: "json"
            }
        );
};
ajaxCall();
share|improve this answer
Thank you for the winner_id.toString() idea. I implemented it, however I'm still unable to get it in my php script – user2330619 Apr 29 at 5:09
Not necessary unless you are giving the response of ajax as json @Charlene Lauron – User016 Apr 29 at 5:16
hmm but the function is passing json data to php, ok i'll test it.. thanks @Deepu – Charlene Lauron Apr 29 at 5:19

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