scroll.js

    var setupLTIScrollRequest = function() {
      window.addEventListener('message', function(e) {
        try {
          var message = JSON.parse(e.data);
          if (message.subject === 'lti.scrollTop') {
            $('html,body').animate({
              scrollTop: $('.tool_content_wrapper').offset().top + message.scrollTop
            }, message.animate);
          }
        } catch(err) {
          (console.error || console.log)('invalid lti message from ' + e.origin);
        }
      });
    };