How to call function from jquery to php?

Question

PHP:

$product_code = $_GET['product_code'];
$countryCode = getCountryCode();
<script src="js/register_script.js" type="text/javascript"></script>

Jquery:

function getCountryCode() {
    countryCode = qrcode_getinfo(qrCode1,"mfg_c_a_code",0)
    return countryCode;
}

I want to get my country code from the jquery to perform some validation task, however, i wasn't able to retrieve the country code. Any idea what should i do for it to work? please note that the library is already been called. (I had read up on examples but dont really understand how it works..)

i think it is not possible because jquery runs on clientside while php runs on server side — guradio
– guradio, Commented Sep 21, 2015 at 8:08
or just use PHP to echo your country code into your javascript on page load. — DevDonkey
– DevDonkey, Commented Sep 21, 2015 at 8:11
include your javascript file before calling the required function — Amani Ben Azzouz
– Amani Ben Azzouz, Commented Sep 21, 2015 at 8:11
The countryCode are store inside the jquery. However i need to validate it with my userId (store in the session and only php file can retrieve it) in the php file — Yan Shuang Low
– Yan Shuang Low, Commented Sep 21, 2015 at 8:20

MartyB · Accepted Answer · 2015-09-23 06:52:14Z

4

It is not possible to directly call PHP function from JavaScript and vice versa. Part of the reason for this is that as @Pekka indicated JS runs clientside (in your browser) while PHP runs server-side (on your server).

It is however possible to use AJAX for your purposes:

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>

<script type="text/javascript">
function getCountryCode()
{
    countryCode = qrcode_getinfo(qrCode1,"mfg_c_a_code",0)
    return countryCode;
}   

function doAjax(){
    var countryCode = getCountryCode();
    $.ajax({
        'url'     : '<THE_URL_TO_YOUR_PHP>?countryCode=' + countryCode,
        'method'  : 'GET',
        'success'  : function(data){
             console.log(data);
             // do your handling here
        },
        'error'   : function(data){
            console.log(error);
            // this function is executed on an HTTP error
        }
    });
}
</script>

PHP

This is your php file that would do your validation. In principle it is a different file than the file that outputs the html as shown above.

$countrycode = $_GET['countryCode'];
# handle countrycode
echo "<What you want to return to JS>";

Edit

On the additional question of how to get session variables to js.

Would I navigate to your page in my browser, the following would happen: If I requested a file with an .php extension, the PHP processer gets run on it. This processer identifies all code between the tags <?php and ?> as PHP, and thus runs all this code. If it encounters an echo statement, it echo's out the specific value at the location of the php-block. After PHP is done processing, the page is served (given) to your browser, where it will be interpreted as a combination of HTML/javascript/... Javascript interprets everything between the tags <script> and </script> as javascript.

So, what if we where to make a request to index.php?par=val on your server, and index.php looks like

<script type="text/javascript">
    function doStuff(){
        var param = <?php echo json_encode($_GET['par']);?>;
    }
</script>

(the json_encode function ensures that the variable is in proper json format. Of course you can change the `$_GET['par']; to be whatever you would like.)

Remember, PHP only cares about whats between the <?php and ?> tags, so this would output:

<script type="text/javascript">
    function doStuff(){
        var param = "val";
    }
</script>

You will need to edit this to match your requirements of course, but this is the basics of passing parameters from PHP to client-side (JS)

edited Sep 23, 2015 at 6:52

answered Sep 21, 2015 at 8:18

MartyB

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8 Comments

Yan Shuang Low Over a year ago

You might be right however my url contain a get method (eg. test.php?test="A12") before the validation. What about is there any way to get the session from php to jquery? If can, i can do the validation there

MartyB Over a year ago

Take a look at this page :)

Yan Shuang Low Over a year ago

Thank you @MartyB, it seem useful

Yan Shuang Low Over a year ago

Tried to understand the codes.. but don't really understand since it is quite different from mine. Can help me simplified to my question?

Yan Shuang Low Over a year ago

You might have misunderstood my question. I want to get data from JS to PHP and not the other way round.

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