Changing button states (Bootstrap)

button.html

<button class="btn save-button primary" type="submit" data-startmsg="Save" data-loadingmsg="Saving..." data-successmsg="Saved!">Save</button>

button.js

function setupFormSave(target, form, callback) {
    var button = form.find('button[type="submit"]');

    button.click(function(event) {
      event.preventDefault();
      button.html(button.attr('data-loadingmsg'));
      button.attr('disabled', true);
      sendForm(target, form, handleResponse);
    });

    function handleResponse(data) {
      if (data.status == 'success') {
          button.html(button.attr('data-successmsg'));
      } else {
          button.html(button.attr('data-startmsg'));
          button.attr('disabled', false);
          renderErrors(data.errors);
      }
    }
  }

how do you use this? thx should the script replace a code in button.js or it can be implemented separately?