IDBRequest.source

var title = "Walk dog";

// Open up a transaction as usual
var objectStore = db.transaction(['toDoList'], "readwrite").objectStore('toDoList');

// Get the to-do list object that has this title as its title
var objectStoreTitleRequest = objectStore.get(title);

objectStoreTitleRequest.onsuccess = function() {
  // Grab the data object returned as the result
  var data = objectStoreTitleRequest.result;

  // Update the notified value in the object to "yes"
  data.notified = "yes";

  // Create another request that inserts the item
  // back into the database
  var updateTitleRequest = objectStore.put(data);

  // Log the source of this request
  console.log("The source of this request is " + updateTitleRequest.source);
  // When this new request succeeds, run the displayData()
  // function again to update the display
  updateTitleRequest.onsuccess = function() { displayData(); };
};