Pass javascript variable to php code?

Question

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How to pass a variable / data from javascript to php and vice versa?

I have a file of php and javascript code. I want to set a php variable to be the result of a javascript function which takes a php variable as a parameter. For example:

$parameter = "this is a php variable";
$phpVar = echo "foo(" . parameter . ");";

I know you cannot do a "= echo", is there another way I can do this?

Thanks

Send using ajax, or using a form ... Depend on your case too, on what you wanna do .. — StiveKnx, Mar 08 '12 at 19:29

Mike Tangolics · Accepted Answer · 2012-03-08T19:43:37.180

12

You can't directly do that, since JavaScript runs on the client-side and PHP gets executed on the server-side.

You would need to execute the JavaScript first and then send the result to the server via a FORM or AJAX call.

Here's what that might look like:

PHP

$parameter = "this is a php variable";
echo "var myval = foo(" . parameter . ");";

JavaScript

var myval = foo("this is a php variable"); // generated by PHP

$.ajax({
  type: 'POST',
  url: 'yourphpfile.php',
  data: {'variable': myval},
});

Receiving PHP (yourphpfile.php)

$myval = $_POST['variable'];
// do something

edited Mar 08 '12 at 19:43

answered Mar 08 '12 at 19:31

Mike Tangolics

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4

The receiving PHP code is the file specified by yourphpfile.php. It can either be separate or part of an if block in the original PHP file. – Mike Tangolics Mar 08 '12 at 19:39
Eloquent and easy to do. – Jodo1992 Apr 24 '17 at 04:32
what about for multiple variables? – user3560827 Apr 21 '19 at 13:41

score 3 · Answer 2 · answered Mar 08 '12 at 19:30

3

PHP code is run on the server before the response is sent; JavaScript is run after, in the browser. You can't set a PHP variable from JavaScript because there are no PHP variables in the browser, where JavaScript if running. You'll have to use an AJAX request from JavaScript to a PHP script that stores whatever information it is you want to get.

answered Mar 08 '12 at 19:30

Chuck

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Whoever downvoted, it would be more useful to explain what you find objectionable, particularly as everyone who answered after me seems to be saying the same thing I did. Is there some important nuance I got wrong? Do you just not like people named after high-quality ground meats? – Chuck Mar 08 '12 at 19:39

score 3 · Answer 3 · answered Mar 08 '12 at 19:35

3

Try this:

var a = "Result: "+ <?php echo json_encode($parameter); ?>;

answered Mar 08 '12 at 19:35

devasia2112

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score 1 · Answer 4 · answered Mar 08 '12 at 19:30

1

You have to make a GET or POST request to the script from JavaScript.

answered Mar 08 '12 at 19:30

hsz

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score 0 · Answer 5 · answered Mar 08 '12 at 19:33

0

You cannot pass a js variable to php code.
PHP happens to run on the server, a thousand miles away from client, where js is run.

So, you can only call a php script, using js or regular hyperlink.

answered Mar 08 '12 at 19:33

Your Common Sense

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Pass javascript variable to php code?

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