IDBObjectStore.clear()

var request = objectStore.clear();

// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);

DBOpenRequest.onsuccess = function(event) {
  note.innerHTML += '<li>Database initialised.</li>';

  // store the result of opening the database in the db variable.
  // This is used a lot below
  db = DBOpenRequest.result;

  // Clear all the data form the object store
  clearData();
};

function clearData() {
  // open a read/write db transaction, ready for clearing the data
  var transaction = db.transaction(["toDoList"], "readwrite");

  // report on the success of the transaction completing, when everything is done
  transaction.oncomplete = function(event) {
    note.innerHTML += '<li>Transaction completed.</li>';
  };

  transaction.onerror = function(event) {
    note.innerHTML += '<li>Transaction not opened due to error: ' + transaction.error + '</li>';
  };

  // create an object store on the transaction
  var objectStore = transaction.objectStore("toDoList");

  // Make a request to clear all the data out of the object store
  var objectStoreRequest = objectStore.clear();

  objectStoreRequest.onsuccess = function(event) {
    // report the success of our request
    note.innerHTML += '<li>Request successful.</li>';
  };
};