code: function initEmailForm() {
          var newsletterForm = document.getElementById('newsletter-form');
          var submitButton = document.getElementById('newsletter-submit');
          var formDetails = document.getElementById('newsletter-details');
          var emailField = document.querySelector('.mzp-js-email-field');
          var formExpanded = window.getComputedStyle(formDetails).display === 'none' ? false : true;
  
          function emailFormShowDetails() {
              if (!formExpanded) {
                  formDetails.style.display = 'block';
                  formExpanded = true;
              }
          }
  
          emailField.addEventListener('focus', function() {
              emailFormShowDetails();
          });
  
          submitButton.addEventListener('click', function(e) {
              if (!formExpanded) {
                  e.preventDefault();
                  emailFormShowDetails();
              }
          });
  
          newsletterForm.addEventListener('submit', function(e) {
              if (!formExpanded) {
                  e.preventDefault();
                  emailFormShowDetails();
              }
          });
      }
docs: !! This file assumes only one signup form per page !! Expand email form on input focus or submit if details aren't visible