An unobtrusive way to block the page on form submission. Requires jQuery Validation to be active on the form (either directly or via unobtrusive validation), and the submithandlerfix to be applied (https://gist.github.com/danielgreen/5669244). If jQuery Validation is not active on the form then we need another solution e.g. just bind to onsubmit

BlockPageOnSubmit.js

$("form[data-block-page-on-submit]").each(function () {
  $(this).validate().settings.submitHandler = function () {
    window.BlockPage();
    return true;
  };
});