Mobile first Coming Soon page with Js

Thank you, should be fixed! :)

Thank you! I fixed these, but I have no idea how to disable the error message, any suggestions? :D

@vivienbalint The simplest take is to add novalidate attribute to your form html. This way you disable client side validation for a form. In doing so you will also have to use method preventDefault() on your button to prevent it from default behavior which is sending. To do this pass event as argument to your function within eventlistener and then call the method preventDefault() on it (like. event.preventDefault()). You will then have to send the form manually if the input meets your validation in javascript. To do so, add form.submit() when your validation if is true.

1. Add novalidate attribute to form. <form id="form" novalidate>

2. Add the preventDefault() method to your button. Doing that default action that belongs to the event will not occur.

btn.addEventListener("click", (event) => {
  let value = email.value;
  event.preventDefault()   <---- HERE
  validateEmail(value);`
});

1. Add manualy form.submit(). Previously we removed submit event from button and validation from form, so now we have to manually call submit method on form. When our condition with email validation is true simply submit it using form.submit().

function validateEmail(email) {
  if (/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/.test(email)) {
    form.classList.remove("error");
    form.submit(); <---- HERE
  } else {
    form.classList.add("error");
  }
}

Wow, thank you Tediko for your help, fixed it! ;)