Pass PHP variable to javascript

Is there any possibility to pass some PHP variables in javascript so I can use them later?

Only in single.php.
I heard about wp_enqueue_scripts but with that it is neccesary to declare a path to a JS file, but I don`t need one.

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3 comments

  1. Best practice method

    Have a look at wp_localize_script, which is meant to do exactly that.

    But it does require previous usage of wp_enqueue_scripts, hence you will need to move your JS to a separate file indeed.
    It will be worth those few minutes of effort though, for sure.

    function wpse_96370_scripts()
    {
        if ( is_single() ) {
    
            wp_register_script(
               'your_script_handle',
               get_template_directory_uri() . '/js/your-script.js',
               array( /* dependencies*/ ),
               1.0,
               true
           );
    
           wp_enqueue_script( 'your-script-handle' );
    
           $script_params = array(
               /* examples */
               'post' => 99,
               'users' => array( 1, 20, 2049 )
           );
    
           wp_localize_script( 'your-script-handle', 'scriptParams', $script_params );
    
        }
    }
    add_action( 'wp_enqueue_scripts', 'wpse_96370_scripts' );
    

    In the JS you will then be able to use the passed parameters like so:

    var posts = scriptParams.post,
        secondUser = scriptParams.users[1]; /* index starts at 0 */
    
    // iterate over users
    for ( var i = 0; i < scriptParams.users.length; i++ ) {
        alert( scriptParams.users[i] );
    }
    

    [Edit] Your situation

    As per your comment

    I created a new db table with some response.ids from facebook api. This is the table: action_id, user_id,post_id, fb_id where fb_id is response.id from a facebook action. Then in single.php I have a button where if I press I must delete the fb action with api: FB.api('/'+fb.response, 'delete'); where fb.response should be fb_id from table.

    Put the following your theme’s /js/ folder, create it, if it doesn’t exist.
    Let’s call the file fb-response.js:

    jQuery( '#button_id' ).click( function() {
        FB.api( '/' + fbParams.id, 'delete' );
    });
    

    Then register, enqueue and localize as seen above. Assuming that you have the ID you’d like to pass in let’s say $fb_id:

    wp_register_script(
        'fb-response',
         get_template_directory_uri() . '/js/fb-response.js',
         array( 'jquery' ),
         1.0,
         true
    );
    
    wp_enqueue_script( 'fb-response' );
    
    wp_localize_script( 'fb-response', 'fbParams', array( 'id' => $fb_id ) );
    

    N.B. Obviously, the above is assuming this is in a theme. If we’re talking “plugin”, alter locations accordingly.

  2. https://developer.wordpress.org/reference/functions/wp_add_inline_script/ should be a preferred option nowadays

    EDIT:
    From the docs above:

    function mytheme_enqueue_typekit() {
       wp_enqueue_script( 'mytheme-typekit', 'https://use.typekit.net/.js', array(), '1.0' );
       wp_add_inline_script( 'mytheme-typekit', 'try{Typekit.load({ async: true });}catch(e){}' );
    }
    add_action( 'wp_enqueue_scripts', 'mytheme_enqueue_typekit' );
    

    So that you first enqueue the script, and then pass the variables

    Yet this code simply generates the following

    <script type="text/javascript" src="https://use.typekit.net/.js?ver=1.0"></script>
    <script type="text/javascript"> try{Typekit.load({ async: true });}catch(e){} </script>
    

    In my case, I simply expose the data I need directly writing the JavaScript code (in the template) and using a global JS variable with a specific name (haven’t found a better way) (using Timber, pure PHP should be equivalent)

    <script>
        my_global_variable.data1 = {{ custom_timber_function()|json_encode }}
    </script>
    
    $twig->addFunction(new TimberTwig_Function('custom_timber_function', function () {
        return [
          'theme' => get_stylesheet_directory_uri(),
        ];
    }));
    
  3. Having read your comment, I understand you’d like to do something like this:

    // Do something to get the ID
    $facebook_id = ...
    
    // Create and print the button
    echo '<input onclick="FB.api('/'+'.$facebook_id.', 'delete')" />';