<script>
const sheetScriptURL = "https://script.google.com/macros/s/AKfycbz75KwEn0CfeTk8H-1fxFal0Ou2aydbEDqbY8MEJxfASNHu8k-3SQD2QZLh3-hT64o4/exec"

function submitNewsletterForm(event) {
  event.preventDefault();

  const name = document.getElementById("name").value.trim();
  const email = document.getElementById("email").value.trim();
  const responseMessage = document.getElementById("responseMessage");

  if (!name || !email) {
    responseMessage.style.color = "red";
    responseMessage.textContent = "fill out all fields";
    return;
  }

  fetch(sheetScriptURL, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ name, email })
  })
    .then(response => response.json())
    .then(data => {
      responseMessage.style.color = "green";
      responseMessage.textContent = "you're part of the journey";
      document.getElementById("newsletterForm").reset();
    })
    .catch(error => {
      responseMessage.style.color = "red";
      responseMessage.textContent = "something went wrong. try again.";
      console.error("Error!", error.message);
    });
}

// fade-in + attach form handler
document.addEventListener("DOMContentLoaded", function () {
  const formEl = document.querySelector(".newsletter-signup");
  const observer = new IntersectionObserver(function (entries) {
    entries.forEach(function (entry) {
      if (entry.isIntersecting) {
        formEl.style.opacity = 1;
        formEl.style.transform = "translateY(0)";
      }
    });
  });
  observer.observe(formEl);

  document.getElementById("newsletterForm").addEventListener("submit", submitNewsletterForm);
});
<script>