Test IndexedDB's create and removeObjectStore On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". dbname = "create-and-remove-object-store.html" indexedDB.deleteDatabase(dbname) indexedDB.open(dbname) db.createObjectStore('tmp') Expecting exception from db.createObjectStore('tmp') PASS Exception was thrown. PASS code is 0 PASS ename is 'ConstraintError' Exception message: Failed to execute 'createObjectStore' on 'IDBDatabase': An object store with the specified name already exists. trans = db.transaction(['tmp']) trans.objectStore('tmp').get(0) PASS event.target.result is undefined. Trying create Expecting exception from db.createObjectStore("some os") PASS Exception was thrown. PASS code is DOMException.INVALID_STATE_ERR PASS ename is 'InvalidStateError' Exception message: Failed to execute 'createObjectStore' on 'IDBDatabase': The database is not running a version change transaction. Trying remove Expecting exception from db.deleteObjectStore("some os") PASS Exception was thrown. PASS code is DOMException.INVALID_STATE_ERR PASS ename is 'InvalidStateError' Exception message: Failed to execute 'deleteObjectStore' on 'IDBDatabase': The database is not running a version change transaction. Trying create with store that already exists Expecting exception from db.createObjectStore('tmp') PASS Exception was thrown. PASS code is DOMException.INVALID_STATE_ERR PASS ename is 'InvalidStateError' Exception message: Failed to execute 'createObjectStore' on 'IDBDatabase': The database is not running a version change transaction. Trying remove with store that already exists Expecting exception from db.deleteObjectStore('tmp') PASS Exception was thrown. PASS code is DOMException.INVALID_STATE_ERR PASS ename is 'InvalidStateError' Exception message: Failed to execute 'deleteObjectStore' on 'IDBDatabase': The database is not running a version change transaction. PASS successfullyParsed is true TEST COMPLETE