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3

How do I define a variable in javascript with echo function, from the external php file?

We have theconfigfile.php, thejsfile.js and thephpfile.php.

In theconfigfile.php we have:

<?php
$path = 'http://example.com/home.php'; // Set your path
?>

In thejsfile.js we have:

... 
if (confirm("Are you sure you want to delete")) {
        $.ajax({
            type: "POST",
            url: "http://example.com/home.php",
            data: dataString,
            cache: false
        });
...

And in thephpfile.php we have:

    <php 
    include "theconfigfile.php";
    ?>

    <html>
    <head>
    <script type="text/javascript" src="thejsfile.js"></script>
    </head>

<body>
...here is the code that uses file thejsfile.js...
</body>
</html>

I used this method:

... 
if (confirm("Are you sure you want to delete")) {
        $.ajax({
            type: "POST",
            url: "<?php echo $path; ?>",
            data: dataString,
            cache: false
        });
...

Only works when javascript is part of the code. And if I use it external, like this...

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

...does not work! Solutions?

share|improve this question
    
Why would you want to echo the path via php? Why not just do it in javascript by hard coding the url, or assigning the path into a variable for later use? –  Dennis Martinez Dec 5 '12 at 23:24
    
Using ajax with inline php seems contradictory, not the best idea IMO. –  elclanrs Dec 5 '12 at 23:26
    
Because i have many files, and i want to modify from one file. –  GAD Dec 5 '12 at 23:26

6 Answers 6

up vote 3 down vote accepted

There are a couple of ways you can go about doing this.

You can configure your webserver to process files with extension .js with PHP and just inject your PHP there. Of course this means you need a way to actually calculate you variable there, adn this would slow down serving your regular javascript content.

You can simply output the PHP variable to a javascipt variable within the a <script> element like this

<script type="text/javascript">
var path = "<?php echo $path; ?>";
</script>

And then access this path variable in your AJAX.

Most would probably use the second approach.

share|improve this answer
1  
THE BEST! WORKS! Thanks you for helping. :) –  GAD Dec 5 '12 at 23:42
1  
Keep in mind, if any other scripts use a variable called path, this could break them. –  DC_ Dec 5 '12 at 23:43
    
Yes I now, I will modify with a new name. Tks! –  GAD Dec 5 '12 at 23:47
    
@DC_ Yes this approach does tend to pollute the global javascript scope, so it would not be recommended to do this alot. If you find yourself outputting a lot of variables in this way, it might be best to output a single js object with config variables inside of it such as to only take up a single base variable name in scope. –  Mike Brant Dec 5 '12 at 23:48
up vote 4 down vote

You can rename your thejsfile.js to thejsfile.php, add the following to the very beginning of it, and it should be parsed for PHP:

<?php header("Content-type: text/javascript"); ?>

Then reference it like this:

<head>
<script type="text/javascript" src="thejsfile.php"></script>
</head>

Your other option is to just set your server up to parse .js files for PHP.

share|improve this answer
    
Thanks a lot, with this works! :) –  GAD Dec 5 '12 at 23:42
up vote 2 down vote

In thephpfile.php,

<html>
<head>
<script type="text/javascript">
    var config = { url: '<?= $path; ?>' };
</script>
<script type="text/javascript" src="thejsfile.js"></script>
</head>

Then you can access it with config.url in your javascript.

share|improve this answer
    
It is a great idea, I used this method: <script type="text/javascript"> var path = "<?php echo $path; ?>"; </script> BUT THANKS A LOT! –  GAD Dec 5 '12 at 23:41
    
I'd try and keep your config seperate, just assigning a variable path could have issues with other scripts. This gives you a nice clean object to expand into if you need to. –  shapeshifter Dec 5 '12 at 23:47
up vote 0 down vote

You can put values in such way only into the files which are processed by PHP.
External JavaScript-files are not processed by PHP so they are linked as is without sustitution.

share|improve this answer
up vote 0 down vote

Unless you're making a post to another server via JSONP then you might just consider using a relative path hard-coded in your Javascript that way you don't need to send the path from the server to the client:

...
    $.ajax({
        type: "POST",
        url: "home.php",
        data: dataString,
        cache: false
    });
....

But, if this is a URL that changes frequently and it really does need to be configurable then you can echo out the PHP variable as script something like this"

<html>
...
<script src="thejsfile.js" type="text/javascript">
<script type="text/javascript">
    // 'path' is a variable that is defined in thejsfile.js
    path = '<?php echo htmlentities($path)  ?>';
</script>

...

Whenever you output info from the server to the client (especially as Javascript) you have to be REALLY careful that it is escaped to prevent scripting attacks (ie allowing people to inject javascript into your code). In this case there is no reason to allow any type of html characters.

share|improve this answer
    
Yes, and works like this! :) –  GAD Dec 5 '12 at 23:43
up vote 0 down vote

When working with external JS files You could store the value in a hidden field and retrieve the fields value with JavaScript.

<input type="hidden" name="path" id="path" value="<?php echo $path; ?>" />

and in the javascript (i'll use jquery)

var path = $('#path').attr('value');

Obviously you could write the variable to the script tags on the page, but if you use any advanced type of patterns it may be hard to access that variable.

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