Un formulario para Svelte sin servidor.

<form action="https://mailcontact.app/api/forms/your-form-id" method="POST" data-mailcontact-form lang="es" data-mailcontact-language="es">
  <input type="hidden" name="_language" value="es" />
  <fieldset>
    <legend>Contáctanos</legend>
    <label>
      Nombre (opcional)
      <input name="name" type="text" autocomplete="name" maxlength="200" />
    </label>
    <label>
      Correo electrónico
      <input name="email" type="email" autocomplete="email" maxlength="320" required />
    </label>
    <label>
      Mensaje
      <textarea name="message" rows="5" maxlength="5000" required></textarea>
    </label>
    <noscript>
    <div aria-hidden="true" style="position:absolute;left:-10000px;width:1px;height:1px;overflow:hidden;">
      <label>Sitio web
        <input name="company_website" type="text" tabindex="-1" autocomplete="off" />
      </label>
    </div>
    </noscript>
    <button type="submit">Enviar mensaje</button>
  </fieldset>
  <p data-contact-status role="status" aria-live="polite" aria-atomic="true"></p>
</form>
<script defer src="https://mailcontact.app/forms/v1.js" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

<script>
  let sent = $state(false);
  let error = $state(false);

  async function submit(event) {
    const res = await fetch("https://mailcontact.app/api/forms/your-form-id", {
      method: "POST",
      body: new FormData(event.currentTarget),
    });
    if (res.ok) sent = true;
    else error = true;
  }
</script>

{#if sent}
  <p>Thanks. We'll be in touch.</p>
{:else}
  <form onsubmit={(e) => { e.preventDefault(); submit(e); }}>
    <input name="name" placeholder="Your name" required />
    <input name="email" type="email" placeholder="[email protected]" required />
    <textarea name="message" placeholder="What's on your mind?" required></textarea>
    <input name="company_website" type="text" tabindex="-1" autocomplete="off"
      style="position:absolute;left:-10000px" aria-hidden="true" />

    <button>Send</button>
    {#if error}<p role="alert">That didn't send. Try again?</p>{/if}
  </form>
{/if}