在Wordpress中：使用AJAX发布jQuery变量，以便以后在PHP中使用

Question

In WordPress, I'm trying to post a jQuery variable using AJAX to use later in PHP. I've setup my jQuery function and the function to echo the variable.

I am getting the success message from the jQuery function in the console log, but the $_POST variable is null.

Below are the functions I've setup:

function foo_carousel_js() { ?>
     <script>
     jQuery(document).ready(function($) {
       var ajax_url = "<?php echo admin_url('admin-ajax.php'); ?>";
       var count_ci = $('.selector li').length;

       $.ajax({
          type: 'POST',   
          url: ajax_url,  
          data: {
            action : 'foo_item_count',
            count_ci : count_ci
          },
          success:function( data ) {
            console.log( data );
          }
       });
    });
   </script>
<?php }
add_action( 'wp_footer', 'foo_carousel_js' );

function foo_item_count() {

    $k = esc_html( $_POST['count_ci'] );
    echo $k;

    wp_die(); 
}
add_action('wp_ajax_foo_item_count', 'foo_item_count');
add_action('wp_ajax_nopriv_foo_item_count', 'foo_item_count');

Answer 1

I had the exact same question/problem a few years ago. Turns out you cannot access that Ajax sent value anywhere else within WP besides your functions.php and of course plugin files. Reason being that while doing Ajax, WP only reloads the mentioned files (functions and plugins) but not the rest of the template structure. Therefore, while $_POST has your data, you can't render it on a template file because those are already loaded.

Edit:

Even within the plugin files, you only have access to your $_POST values within an Ajax handler function.

I recommend rethinking your goal, maybe Ajax isn't the way to go.