This JS snipped makes the subscription modal in a Statuspal status page to open with the "Select services" option checked by default.

statuspal_subscription_modal_mod.js

document.addEventListener("DOMContentLoaded", function() {
  var $ = document.querySelector.bind(document);
  var subButton = $('.subscribe');
  var input = $('[name="subscription[filter]"][value="services"]');
  subButton.addEventListener('click', function () {
    setTimeout(function () {
      input.checked = true;
      input.dispatchEvent(new Event('change'));
    }, 0);
  });
});