Divi theme – Page reload when clicking a button Javascript, HTML

I have an issue when clicking a button. My page reload and the message “MERCI, VEUILLEZ VÉRIFIER VOS MESSAGES” doesn’t display. I don’t know if these two issues are linked. I’m on WordPress, Chrome, with DIVI themes. and I don’t have error in console.

HTML:

<form class="formnumber">
  <input class="inputsms" id="number" placeholder="ENTREZ VOTRE NUMÉRO" />
  <button class="buttonsms" id="buttonsms">ENVOYER ></button>
</form>

JavaScript:

var button = document.getElementById('buttonsms');


if(button){
button.addEventListener('click', function(e) {
  e.preventDefault();
  this.classList.add('is-done');

  setTimeout(function() {
    button.innerHTML = "MERCI, VEUILLEZ VÉRIFIER VOS MESSAGES 😍"
  }, 500);
});
}

You can see all the code with CSS and animation here