How to use a php variable in an external javascript code?

Question

Usually, when i need to use some php in javascript code, i use to put the code into the head like this :

<script>
    $(function() {

    $("input#datepicker").val('<?php echo $date ?>');
});
</script>

This way, i can use some php variables in javascript code. It works fine.

Do you know how to do this if i want to put all javascript code in an external js file :

<script type="text/javascript" src="js/admin.js"></script>

Maybe it doesn't matter at all. But i use to code in an external js file and and i'm wondering if it's possible to do that.

I wanted to do this once and was persuaded not to. The issues are (a) having to put .js files through the PHP parser, and (b) needing to adopt measures to avoid caching. — Beetroot-Beetroot
– Beetroot-Beetroot, Commented Jan 17, 2013 at 21:20

Get Off My Lawn · Accepted Answer · 2013-01-17 21:26:03Z

4

You would need to make the js file a php file.

<script type="text/javascript" src="js/admin.php"></script>

If you still want to keep the js extension, you need to do a rewrite for your webserver.

js/admin.php

<?php
header("content-type: text/javascript");
?>
$(function() {
    $("input#datepicker").val('<?php echo $date ?>');
});

if you want the js extension here is an example rewrite.

Nginx

rewrite /js/admin.js /js/admin.php;

Apache

RewriteEngine On
RewriteBase /
rewrite /js/admin.js /js/admin.php;

edited Jan 17, 2013 at 21:26

answered Jan 17, 2013 at 21:18

Get Off My Lawn

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5 Comments

Sébastien Gicquel Over a year ago

In admin.php (with .php), do i need to use <script></script> ?

Get Off My Lawn Over a year ago

Nope, you would use it like a normal js file with php in it

Get Off My Lawn Over a year ago

depends on where date comes from

Sébastien Gicquel Over a year ago

$date comes from a query from database : $date = $data['date_publication'];

Get Off My Lawn Over a year ago

So in that case, $date won't work unless the query is in the javascript file.

Mohammad Hossein Fattahizadeh · Accepted Answer · 2013-01-17 21:23:46Z

1

It's better to cache your js into client browser and just send the variable to client. if you serve all js as new response. think about bandwidth and another request to your web server.

<script type="text/javascript" src="js/admin.js"></script>
<script type="text/javascript">
    var myVar = <?php echo json_encode($myVar); ?>;

    myAdminFunction(myVar);
</script>

answered Jan 17, 2013 at 21:23

Mohammad Hossein Fattahizadeh

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