Inline Manual Player: simple undo

simple_undo.js

// call this function to display previous step
function activatePreviousStep () {
  var previous_topic = localStorage.getItem('inm_previous_topic');
  var previous_step = localStorage.getItem('inm_previous_step');
  inline_manual_player.activateStep(previous_topic, previous_step);
}

// remember topic/step whenever step is deactivated
// e.g. when user goes to next step
inline_manual_player.setOptions({
  callbacks: {
    onStepDeactivate: function (player, topic_id, step_index) {
      localStorage.setItem('inm_previous_topic', topic_id);
      localStorage.setItem('inm_previous_step', step_index);
    }
  }
});