passing php variable to separate javascript file

Question

I have been reading how to pass variables from a php webpage to a separate javascript file, but am not having any luck.

Please don't mark this as duplicate, as I know there are a ton of things out there telling the ways to do this. I recognize those posts and am more just checking my syntax or seeing if there is anything unique about my specific situation that is causing those methods not to work.

So I have a PHP webpage where I POSTed some variables to:

DOCTYPE HTML

...

 <?php
            $id = $_POST["id"];
            $name = $_POST["name"];
    ?>
...

HTML code with some usage of PHP variables

javascriptFunction()

end page

Then in a separate javascript file I have:

var markerlocation = '<?php echo $point; ?>'; 

function javascriptFunction () {

alert("markerlocation");

});

This seems really straight forward, but for whatever reason I can't get it. I also have tried with json encode.

I can delete this when done. Sincere thanks for any help.

You can't run php script when u are separated to a javascript file — Parfait
– Parfait, Commented Oct 23, 2014 at 5:33
Or you could have the first script pass the variable as a parameter when it calls javascriptFunction(). — Barmar
– Barmar, Commented Oct 23, 2014 at 5:38
What is the file name? If it has the .js extension and not the .php extension your server won't know to execute it as a php file. — Chad Hedgcock
– Chad Hedgcock, Commented Oct 23, 2014 at 5:42
@ambe5950- you need to understand - if you don't already - that Javascript and PHP are executed at completely different times, in completely different places. PHP is executed on the server. It's output is the HTML that is sent to the browser. Your Javascript is part of that HTML. It's executed only after PHP has done it's job, and the browser is evaluating your HTML. Look at Partfair's solution - it'a good example of how you can "pass data" from PHP (on the server) to Javascript. Be sure to do a "View Source" on the browser to see how <?= .. ?> is altered before it leaves the server. — paulsm4
– paulsm4, Commented Oct 23, 2014 at 5:48

Parfait · Accepted Answer · 2014-10-23 05:41:11Z

2

My way:

Declare a Array to store variable for passing variable to JavaScript
Encode the Array to JSON in php
Decode the JSON String from php and store as a JavaScript variable

PHP

<?php
    //You may declare array for javascript
    $jsVal = array(
        'user_name' => 'Peter',
        'email' => '[email protected]',
        'marker_location' => '102,300'
    );
?>  

<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script>var phpConfig = jQuery.parseJSON(<?=json_encode($jsVal)?>);</script>

Separated javascript file

alert(phpConfig.marker_location);

You can try it

answered Oct 23, 2014 at 5:41

Parfait

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Jonathan Gray · Accepted Answer · 2014-10-23 05:46:36Z

0

You can point the script tag source to a .php file instead of a .js file, I think that's what you want. Works with image tags too ;)

Edit: some browsers may require the text/javascript mime header in order for it to work properly, but it's not hard with PHP I'll assume you already know how to do that.

On a side note: This option should probably only be used if you're planning on allowing the client to cache the javascript output. If you don't want the client to cache it, you need to set additional headers.

edited Oct 23, 2014 at 5:46

answered Oct 23, 2014 at 5:41

Jonathan Gray

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