doctype html html head title Join the #{community} community on Slack! style. body { padding: 50px; font: 14px "Lucida Grande", Helvetica, Arial, sans-serif; } input { font-size: 24px; width: 400px; } body h1 Join the #{community} community on Slack! form(method="POST", action="/invite")#join-form input(type="text", name="email", placeholder="Enter your email")#slack-email script. var form = document.getElementById('join-form'); var email = document.getElementById('slack-email') form.addEventListener('submit', function(evt) { if (!email.value) { evt.preventDefault(); } });