Test features of IndexedDB's unique indices. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". indexedDB = self.indexedDB || self.webkitIndexedDB || self.mozIndexedDB || self.msIndexedDB || self.OIndexedDB; indexedDB.deleteDatabase(dbname) indexedDB.open(dbname) db.createObjectStore('store') store.createIndex('index', 'x', {unique: true}) setVersionCompleted(): transaction = db.transaction(['store'], 'readwrite') transaction.objectStore('store').put({x: 1}, 'foo') addMoreData(): transaction.objectStore('store').put({x: 1}, 'bar') addMoreDataFailed(): event.preventDefault() PASS event.target.error.name is 'ConstraintError' transaction.objectStore('store').put({x: 0}, 'foo') changeDataSuccess(): transaction.objectStore('store').index('index').openCursor(IDBKeyRange.lowerBound(1)) cursorSuccess(): PASS event.target.result is null transaction.objectStore('store').index('index').openKeyCursor(IDBKeyRange.lowerBound(1)) keyCursorSuccess(): PASS event.target.result is null transaction.objectStore('store').put({x: 1}, 'bar') addMoreDataSucces(): transaction.objectStore('store').delete('bar') deleteSuccess(): transaction.objectStore('store').put({x: 1}, 'baz') finalAddSuccess(): transaction.objectStore('store').put({x: 1}, 'baz') PASS successfullyParsed is true TEST COMPLETE