site_login/src/js/subscriptions_tab.js

(function($, document) {

  // When the user clicks on the Subscription tab,
  // We load the list of newsletters only once.
  // We prevent the data to be reloaded by adding a "loaded" class to the body
  $(document).on('shown.bs.tab', function (e) {
    function subscription_form(){
      $("#subscription-form-submit").click(function() {
        var text = $(this).text().toLowerCase();
        $(this).html('<i class="fa fa-spinner fa-pulse"></i> ' + text);
        var posting = $.post(url, {
          form_name: 'mailchimp_form',
          stage: 'mailchimp_' + text,
        });

        posting.done(function(data) {
          $(target_id).html(data).addClass('loaded');
          subscription_form();
        });
        return;
      });
    }
    
    var target_id = $(e.target).attr('href');
    if ($(e.target).attr('id') == 'tab-subscriptions' && $(target_id).attr('class').indexOf("loaded") <= 0) {
      var url = $(e.target).attr('data-url');
      if (url.startsWith("https://dev.eclipse.org") || url.startsWith("https://dev.eclipse.local")) {
        // load the URL's html to the target's body
        $.get(url, function(data) {
          $(target_id).html(data).addClass('loaded');
          subscription_form();
        });
      }
    }
  });

})(jQuery, document);