Is there a way to set a php variable via JavaScript

Question

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Using a javascript variable to set PHP variable

I need to do something like this

<script type="text/javascript" charset="utf-8">
    '<?php $something; ?>' = $(".product_calculation").val();
</script>

<?php
  print "from js" . $something;
?>

so i need to set a variable and then use it in php directly below after i set it

Why exactly do you need to do this? PHP is run on your server, and then set to the browser where the JavaScript is ran. Maybe you can use AJAX, or a cookie to send the value to a PHP script? — gen_Eric, Jun 08 '11 at 20:41

score 8 · Accepted Answer · answered Jun 08 '11 at 20:40

8

No you cannot. PHP is executed by your server. jQuery later by clients.
What you can do is an AJAX requests with params.

answered Jun 08 '11 at 20:40

dynamic

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+1 @yes123 honestly, I did not expect correct answer from you :) – Tadeck Jun 08 '11 at 20:43
@Tadeck: lol I know you are ironic there. Thanks anyway – dynamic Jun 08 '11 at 20:44
where would i do the ajax request, in the php or the javascript....basically i have an id on the page and i need to use that id via php – Matt Elhotiby Jun 08 '11 at 20:45
@Tamer: ajax requests in php? I think people with stackoverflow just got more lazy :) – dynamic Jun 08 '11 at 20:46
What do you need to do with the id? Are you just trying to output it somewhere? Or do you need to do stuff with it? – daybreaker Jun 08 '11 at 20:50

score 2 · Answer 2 · answered Jun 08 '11 at 20:41

Short answer: No. Long answer: Yes.

You cannot directly affect PHP variables via jQuery since PHP runs on the server and jQuery runs on the client (after the PHP is already complete). But if you really needed to, you could make AJAX calls to the server to set variable values as long as those variables can be maintained somehow (session, database, flat file, etc) so that the next time the script runs, the value can be retrieved.

score 0 · Answer 3 · answered Jun 08 '11 at 20:42

You will need to do ajax to pass the variable back to the server. While the code is generated on the server it is executed on the Client which the server has no contact with until a request is made.See: http://api.jquery.com/jQuery.ajax/ for info on the jquery implementation.

score 0 · Answer 4 · answered Jun 08 '11 at 20:42

PHP executes server side and outputs HTML and Javascript. Javascript executes afterward on the client's browser. It's not possible.

What you can do instead is have Javascript set a form element or parameter and then pass that to PHP to set it. Or use AJAX as others have suggested.

score 0 · Answer 5 · answered Jun 08 '11 at 20:43

A PHP variable exists only in the web server. Once PHP has been parsed and executed the resulting HTML is sent to your browser. That resulting page would contain your javascript which is then run in the context of the browser. So, no, what you're asking to do is not possible.

score 0 · Answer 6 · answered Jun 08 '11 at 20:48

Not in that fashion. But there are various options to transfer a JS variable to PHP. (Unless you had an PHP application server a direct RPC connection for variable interchanges seems infeasible).

What you commonly can utilize however is a cookie:

document.cookie = "something="+$(".product_calculation").val();

So it will not become $something in PHP, but $_COOKIE["something"] and of course only with the very next page request.

Is there a way to set a php variable via JavaScript

6 Answers6