php variable inside js code

Question

I need a php variable inside js code.
Why this doens't work?

index.php

<?php
$h = 966;
?>

index.js

var b = <?php echo $h;?>;

Error:

Uncaught SyntaxError: Unexpected token <

You can not use php codes in files with format .js!!!! – Mohammad Gholamian Jul 18 '14 at 23:08 — Mohammad Gholamian, Jul 18 '14 at 23:08

username tbd · Accepted Answer · 2014-07-18T23:07:20.803

2

You can't run php inside a JavaScript (.js) file.

Take a look at the question shared by Ed Cottrell in the comment on your post for more information, but basically, PHP is a server language, whereas JavaScript is a client one—when your computer loads index.js, it sees the php script, but has no idea what to do with it.

A straightforward solution (though not the best) would be to output a <script> tag containing your variable inside from your php file— and then access it from your JavaScript file.

edited Jul 18 '14 at 23:07

answered Jul 18 '14 at 22:57

username tbd

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Downvoter, please enlighten me :) – username tbd Jul 18 '14 at 23:00
username tbd, I'm not the downvoter. Thanks for your explanation, but on the given page states that it is possible to echo php variable inside js. This is under accepted answer - part `3. Echo the data directly to JavaScript` – qadenza Jul 18 '14 at 23:04
@bonaca, that's describing the same thing I am at the end of my answer—that code snippet is part of a `.php` file rather than a `.js` one :) For the record, as that page says, it is not the best solution though! – username tbd Jul 18 '14 at 23:06
ok, it's clear now, thanks again. solved. – qadenza Jul 18 '14 at 23:10

score 1 · Answer 2 · answered Jul 18 '14 at 23:07

When your browser requests the Js file, the web server typically simply sends it the file in the response without processing it like a php file. It doesn't know you have php code in it. It does the same (just sends it to the requesting browser) for images, text files, etc.

You can try doing that in your php view/template/script (I would wrap the output in single quotes). Something like:

 <script>var b = '<?php echo $h;?>';</script>

You could also make a JavaScript file with a php extension: index.js.php, and include this instead of index.js. You'll need to set some headers in the top of that file to let the browser know it's getting JavaScript:

 header("content-type: application/javascript");

There is some slightly more advanced stuff you can do as well: use an htaccess file to parse certain requests (like for that Js file) using php, or using an asynchronous request (Ajax) to pull the value of 'b' from the server, but it looks like your doing something a bit more simple.

php variable inside js code

2 Answers2