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I have a problem adding a custom script to my functions.php file:

add_action('wp_print_scripts', 'load_AJAX_URL__');
function load_AJAX_URL__() {
    wp_localize_script( 'ajax_URL', 'MyAjax', array( 'ajaxurl' => admin_url('admin-ajax.php') ) );

Why is not working? any ideas?

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Do you want to use a variable in a js file? – Joshua Abenazer Dec 21 '11 at 18:26
yes, that's I want to do. – greenbandit Dec 21 '11 at 18:38
Please post more of the associated code so we don't have to guess what you have or havn't done..(ie. whether you've register and enqueued scripts). – t31os Dec 21 '11 at 21:47
up vote 3 down vote accepted

The function wp_localize_script() is used to send variables to a script that has already been registered and enqueued. Do you have a js file that has been registered and enqueued and has the handle of 'ajax_URL'? If not, then that explains why it isn't working.

Also, ajaxurl is already a js variable that is accessible via any scripts you enqueue, so I'm not quite sure what you're trying to do here.

If you're just trying to add a new js file into your theme, you want to look at the wp_enqueue_script() function.

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Im Trying to add a variable to use in two different javascripts pointing the same ajax url file. – greenbandit Dec 21 '11 at 18:37
The variable you are trying to pass through is already available by default. – Kevin Langley Jr. Dec 21 '11 at 18:42
Per the codex: Since 2.8 ajaxurl is always defined in the admin header and points to admin-ajax.php codex.wordpress.org/AJAX_in_Plugins – Kevin Langley Jr. Dec 21 '11 at 18:42
Also, keep in mind that like I said, the first paramater in the function wp_localize_script is the handle for the registered js file you are trying to localize. – Kevin Langley Jr. Dec 21 '11 at 18:44
thank you, reading the codex . – greenbandit Dec 21 '11 at 20:13

Ok you can do it this way.

function my_ajax_scripts() {
    $data = array( 'ajaxurl' => admin_url('admin-ajax.php') );
    wp_enqueue_script( 'ajax_url', get_stylesheet_directory_uri() . '/my-custom-ajax.js' );
    wp_localize_script( 'ajax_url', 'MyAjax', $data );
    wp_enqueue_script( 'ajax_url_2', get_stylesheet_directory_uri() . '/my-custom-ajax-2.js' );
    wp_localize_script( 'ajax_url_2', 'MyAjax', $data );
add_action( 'wp_enqueue_scripts', 'my_ajax_scripts' );

You need to enqueue the scripts first and then use wp_localize_script to pass a variable to that file using the handle of that particular js file.

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