umbraco-scroll-to-form.js

  $(document).ready(function () {
    function scrollToFormIfInteractedWith() {
      // Find a target to scroll to if the user is interacting with forms. This happens in different ways:
      // - Find a submit message that is not wrapped in a form (the message is always present even when not visible
      // as the form has just been loaded.
      // - If the message wasn't found then try to target a form containing a hidden field that indicates that the form's
      // step/page is not the first(0) one.
      // - If that wasn't found either then try to find a form that has PreviousClicked = true where the user just
      // navigated back. This is CURRENTLY NOT WORKING possibly because of an Umbraco Forms issue for which I've raise
      // a github issue here https://github.com/umbraco/Umbraco-CMS/issues/4443.
      let target = $('.umbraco-forms-submitmessage:not(form .umbraco-forms-submitmessage)')[0]
          || $('input[type="hidden"][name="FormStep"]:not([value="0"]),'
              + 'input[type="hidden"][name="PreviousClicked"][value="true"]').parent('form')[0];

      // If we have found a target to scroll to then smooth scroll there.
      if (target) {
        // If inside an accordion then click it to expand it.
        $(target).parent('.accordion-panel').children('button.accordion-panel__button').click();
        
        // Scroll page to the target. Here 20 is just to add some margin, but you could need to add
        // the height of your sticky navbar too.
        let targetOffset = $(target).offset().top - 20;
        $('html,body').animate({scrollTop: targetOffset});
      }
    }

    scrollToFormIfInteractedWith();
  });
  
}