[WP AJAX] #ajax

ajax.php

<?php

function exampleAjaxResponse()
{

    die(); // or exit; or wp_die();
}

// Note you need both of them to work for logged in & not logged in users.
add_action('wp_ajax_your_action_name', 'exampleAjaxResponse');
add_action('wp_ajax_nopriv_your_action_name', 'exampleAjaxResponse');

function onlyWorksIfUserLoggedIn()
{
    die(); // or exit; or wp_die();
}
// Note if it should only work for users logged in, do this. Now, it's secure.
add_action('wp_ajax_your_action_name', 'onlyWorksIfUserLoggedIn');

function catchesAVariable()
{
    // be sure to check for empty values and provide a default
    $name = !empty($_POST['name']) ? $_POST['name'] : 'My default value';
    die(); // or exit; or wp_die();
}
add_action('wp_ajax_your_action_name', 'catchesAVariable');

function returningJson()
{
    // be sure to check for empty values and provide a default
    $name = !empty($_POST['name']) ? $_POST['name'] : 'My default value';
    // note - wp_send_json automatically returns json & calls die();
    wp_send_json(['name' => $name]);
}
add_action('wp_ajax_your_action_name', 'returningJson');

function returningHtml()
{
    $page = !empty($_POST['page']) ? $_POST['page'] : 0;
    $html = wp_query_or_something();
    // just echo out the html
    echo $html;
    die();
}
add_action('wp_ajax_your_action_name', 'returningHtml');