--- a/dom/indexedDB/ActorsChild.cpp
+++ b/dom/indexedDB/ActorsChild.cpp
@@ -2486,16 +2486,20 @@ BackgroundRequestChild::Recv__delete__(c
       case RequestResponse::TObjectStorePutResponse:
         HandleResponse(aResponse.get_ObjectStorePutResponse().key());
         break;
 
       case RequestResponse::TObjectStoreGetResponse:
         HandleResponse(aResponse.get_ObjectStoreGetResponse().cloneInfo());
         break;
 
+      case RequestResponse::TObjectStoreGetKeyResponse:
+        HandleResponse(aResponse.get_ObjectStoreGetKeyResponse().key());
+        break;
+
       case RequestResponse::TObjectStoreGetAllResponse:
         HandleResponse(aResponse.get_ObjectStoreGetAllResponse().cloneInfos());
         break;
 
       case RequestResponse::TObjectStoreGetAllKeysResponse:
         HandleResponse(aResponse.get_ObjectStoreGetAllKeysResponse().keys());
         break;
 

--- a/dom/indexedDB/ActorsParent.cpp
+++ b/dom/indexedDB/ActorsParent.cpp
@@ -8180,33 +8180,34 @@ private:
 
   virtual nsresult
   DoDatabaseWork(DatabaseConnection* aConnection) override;
 
   virtual void
   GetResponse(RequestResponse& aResponse) override;
 };
 
-class ObjectStoreGetAllKeysRequestOp final
+class ObjectStoreGetKeyRequestOp final
   : public NormalTransactionOp
 {
   friend class TransactionBase;
 
-  const ObjectStoreGetAllKeysParams mParams;
+  const uint32_t mObjectStoreId;
+  const OptionalKeyRange mOptionalKeyRange;
+  const uint32_t mLimit;
+  const bool mGetAll;
   FallibleTArray<Key> mResponse;
 
 private:
   // Only created by TransactionBase.
-  ObjectStoreGetAllKeysRequestOp(TransactionBase* aTransaction,
-                                 const ObjectStoreGetAllKeysParams& aParams)
-    : NormalTransactionOp(aTransaction)
-    , mParams(aParams)
-  { }
-
-  ~ObjectStoreGetAllKeysRequestOp()
+  ObjectStoreGetKeyRequestOp(TransactionBase* aTransaction,
+                             const RequestParams& aParams,
+                             bool aGetAll);
+
+  ~ObjectStoreGetKeyRequestOp()
   { }
 
   virtual nsresult
   DoDatabaseWork(DatabaseConnection* aConnection) override;
 
   virtual void
   GetResponse(RequestResponse& aResponse) override;
 };
@@ -14524,16 +14525,32 @@ TransactionBase::VerifyRequestParams(con
       }
       if (NS_WARN_IF(!VerifyRequestParams(params.keyRange()))) {
         ASSERT_UNLESS_FUZZING();
         return false;
       }
       break;
     }
 
+    case RequestParams::TObjectStoreGetKeyParams: {
+      const ObjectStoreGetKeyParams& params =
+        aParams.get_ObjectStoreGetKeyParams();
+      const RefPtr<FullObjectStoreMetadata> objectStoreMetadata =
+        GetMetadataForObjectStoreId(params.objectStoreId());
+      if (NS_WARN_IF(!objectStoreMetadata)) {
+        ASSERT_UNLESS_FUZZING();
+        return false;
+      }
+      if (NS_WARN_IF(!VerifyRequestParams(params.keyRange()))) {
+        ASSERT_UNLESS_FUZZING();
+        return false;
+      }
+      break;
+    }
+
     case RequestParams::TObjectStoreGetAllParams: {
       const ObjectStoreGetAllParams& params =
         aParams.get_ObjectStoreGetAllParams();
       const RefPtr<FullObjectStoreMetadata> objectStoreMetadata =
         GetMetadataForObjectStoreId(params.objectStoreId());
       if (NS_WARN_IF(!objectStoreMetadata)) {
         ASSERT_UNLESS_FUZZING();
         return false;
@@ -14986,20 +15003,24 @@ TransactionBase::AllocRequest(const Requ
         new ObjectStoreGetRequestOp(this, aParams, /* aGetAll */ false);
       break;
 
     case RequestParams::TObjectStoreGetAllParams:
       actor =
         new ObjectStoreGetRequestOp(this, aParams, /* aGetAll */ true);
       break;
 
+    case RequestParams::TObjectStoreGetKeyParams:
+      actor =
+        new ObjectStoreGetKeyRequestOp(this, aParams, /* aGetAll */ false);
+      break;
+
     case RequestParams::TObjectStoreGetAllKeysParams:
       actor =
-        new ObjectStoreGetAllKeysRequestOp(this,
-                                     aParams.get_ObjectStoreGetAllKeysParams());
+        new ObjectStoreGetKeyRequestOp(this, aParams, /* aGetAll */ true);
       break;
 
     case RequestParams::TObjectStoreDeleteParams:
       actor =
         new ObjectStoreDeleteRequestOp(this,
                                        aParams.get_ObjectStoreDeleteParams());
       break;
 
@@ -25887,67 +25908,88 @@ ObjectStoreGetRequestOp::GetResponse(Req
 
     nsresult rv = ConvertResponse(0, serializedInfo);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       aResponse = rv;
     }
   }
 }
 
-nsresult
-ObjectStoreGetAllKeysRequestOp::DoDatabaseWork(DatabaseConnection* aConnection)
+ObjectStoreGetKeyRequestOp::ObjectStoreGetKeyRequestOp(
+                                                  TransactionBase* aTransaction,
+                                                  const RequestParams& aParams,
+                                                  bool aGetAll)
+  : NormalTransactionOp(aTransaction)
+  , mObjectStoreId(aGetAll ?
+                     aParams.get_ObjectStoreGetAllKeysParams().objectStoreId() :
+                     aParams.get_ObjectStoreGetKeyParams().objectStoreId())
+  , mOptionalKeyRange(aGetAll ?
+                        aParams.get_ObjectStoreGetAllKeysParams()
+                               .optionalKeyRange() :
+                        OptionalKeyRange(aParams.get_ObjectStoreGetKeyParams()
+                                                .keyRange()))
+  , mLimit(aGetAll ? aParams.get_ObjectStoreGetAllKeysParams().limit() : 1)
+  , mGetAll(aGetAll)
+{
+  MOZ_ASSERT(aParams.type() == RequestParams::TObjectStoreGetKeyParams ||
+             aParams.type() == RequestParams::TObjectStoreGetAllKeysParams);
+  MOZ_ASSERT(mObjectStoreId);
+  MOZ_ASSERT_IF(!aGetAll,
+                mOptionalKeyRange.type() ==
+                  OptionalKeyRange::TSerializedKeyRange);
+}
+
+nsresult
+ObjectStoreGetKeyRequestOp::DoDatabaseWork(DatabaseConnection* aConnection)
 {
   MOZ_ASSERT(aConnection);
   aConnection->AssertIsOnConnectionThread();
 
   PROFILER_LABEL("IndexedDB",
-                 "ObjectStoreGetAllKeysRequestOp::DoDatabaseWork",
+                 "ObjectStoreGetKeyRequestOp::DoDatabaseWork",
                  js::ProfileEntry::Category::STORAGE);
 
   const bool hasKeyRange =
-    mParams.optionalKeyRange().type() == OptionalKeyRange::TSerializedKeyRange;
+      mOptionalKeyRange.type() == OptionalKeyRange::TSerializedKeyRange;
 
   nsAutoCString keyRangeClause;
   if (hasKeyRange) {
-    GetBindingClauseForKeyRange(
-      mParams.optionalKeyRange().get_SerializedKeyRange(),
-      NS_LITERAL_CSTRING("key"),
-      keyRangeClause);
+    GetBindingClauseForKeyRange(mOptionalKeyRange.get_SerializedKeyRange(),
+                                NS_LITERAL_CSTRING("key"),
+                                keyRangeClause);
   }
 
   nsAutoCString limitClause;
-  if (uint32_t limit = mParams.limit()) {
+  if (mLimit) {
     limitClause.AssignLiteral(" LIMIT ");
-    limitClause.AppendInt(limit);
+    limitClause.AppendInt(mLimit);
   }
 
   nsCString query =
     NS_LITERAL_CSTRING("SELECT key "
                        "FROM object_data "
                        "WHERE object_store_id = :osid") +
     keyRangeClause +
     NS_LITERAL_CSTRING(" ORDER BY key ASC") +
     limitClause;
 
   DatabaseConnection::CachedStatement stmt;
   nsresult rv = aConnection->GetCachedStatement(query, &stmt);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
-  rv = stmt->BindInt64ByName(NS_LITERAL_CSTRING("osid"),
-                             mParams.objectStoreId());
+  rv = stmt->BindInt64ByName(NS_LITERAL_CSTRING("osid"), mObjectStoreId);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   if (hasKeyRange) {
-    rv = BindKeyRangeToStatement(
-      mParams.optionalKeyRange().get_SerializedKeyRange(),
-      stmt);
+    rv = BindKeyRangeToStatement(mOptionalKeyRange.get_SerializedKeyRange(),
+                                 stmt);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
   }
 
   bool hasResult;
   while(NS_SUCCEEDED((rv = stmt->ExecuteStep(&hasResult))) && hasResult) {
     Key* key = mResponse.AppendElement(fallible);
@@ -25960,28 +26002,42 @@ ObjectStoreGetAllKeysRequestOp::DoDataba
       return rv;
     }
   }
 
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
-  return NS_OK;
-}
-
-void
-ObjectStoreGetAllKeysRequestOp::GetResponse(RequestResponse& aResponse)
-{
-  aResponse = ObjectStoreGetAllKeysResponse();
+  MOZ_ASSERT_IF(!mGetAll, mResponse.Length() <= 1);
+
+  return NS_OK;
+}
+
+void
+ObjectStoreGetKeyRequestOp::GetResponse(RequestResponse& aResponse)
+{
+  MOZ_ASSERT_IF(mLimit, mResponse.Length() <= mLimit);
+
+  if (mGetAll) {
+    aResponse = ObjectStoreGetAllKeysResponse();
+
+    if (!mResponse.IsEmpty()) {
+      nsTArray<Key>& response =
+        aResponse.get_ObjectStoreGetAllKeysResponse().keys();
+      mResponse.SwapElements(response);
+    }
+
+    return;
+  }
+
+  aResponse = ObjectStoreGetKeyResponse();
 
   if (!mResponse.IsEmpty()) {
-    nsTArray<Key>& response =
-      aResponse.get_ObjectStoreGetAllKeysResponse().keys();
-    mResponse.SwapElements(response);
+    aResponse.get_ObjectStoreGetKeyResponse().key() = Move(mResponse[0]);
   }
 }
 
 ObjectStoreDeleteRequestOp::ObjectStoreDeleteRequestOp(
                                          TransactionBase* aTransaction,
                                          const ObjectStoreDeleteParams& aParams)
   : NormalTransactionOp(aTransaction)
   , mParams(aParams)

--- a/dom/indexedDB/IDBObjectStore.cpp
+++ b/dom/indexedDB/IDBObjectStore.cpp
@@ -1697,19 +1697,20 @@ IDBObjectStore::IndexNames()
       listNames.InsertElementSorted(indexes[index].name());
     }
   }
 
   return list.forget();
 }
 
 already_AddRefed<IDBRequest>
-IDBObjectStore::Get(JSContext* aCx,
-                    JS::Handle<JS::Value> aKey,
-                    ErrorResult& aRv)
+IDBObjectStore::GetInternal(bool aKeyOnly,
+                            JSContext* aCx,
+                            JS::Handle<JS::Value> aKey,
+                            ErrorResult& aRv)
 {
   AssertIsOnOwningThread();
 
   if (mDeletedSpec) {
     aRv.Throw(NS_ERROR_DOM_INDEXEDDB_NOT_ALLOWED_ERR);
     return nullptr;
   }
 
@@ -1725,19 +1726,27 @@ IDBObjectStore::Get(JSContext* aCx,
   }
 
   if (!keyRange) {
     // Must specify a key or keyRange for get().
     aRv.Throw(NS_ERROR_DOM_INDEXEDDB_DATA_ERR);
     return nullptr;
   }
 
-  ObjectStoreGetParams params;
-  params.objectStoreId() = Id();
-  keyRange->ToSerialized(params.keyRange());
+  const int64_t id = Id();
+
+  SerializedKeyRange serializedKeyRange;
+  keyRange->ToSerialized(serializedKeyRange);
+
+  RequestParams params;
+  if (aKeyOnly) {
+    params = ObjectStoreGetKeyParams(id, serializedKeyRange);
+  } else {
+    params = ObjectStoreGetParams(id, serializedKeyRange);
+  }
 
   RefPtr<IDBRequest> request = GenerateRequest(aCx, this);
   MOZ_ASSERT(request);
 
   IDB_LOG_MARK("IndexedDB %s: Child  Transaction[%lld] Request[%llu]: "
                  "database(%s).transaction(%s).objectStore(%s).get(%s)",
                "IndexedDB %s: C T[%lld] R[%llu]: IDBObjectStore.get()",
                IDB_LOG_ID_STRING(),

--- a/dom/indexedDB/IDBObjectStore.h
+++ b/dom/indexedDB/IDBObjectStore.h
@@ -198,17 +198,34 @@ public:
          ErrorResult& aRv)
   {
     AssertIsOnOwningThread();
 
     return DeleteInternal(aCx, aKey, /* aFromCursor */ false, aRv);
   }
 
   already_AddRefed<IDBRequest>
-  Get(JSContext* aCx, JS::Handle<JS::Value> aKey, ErrorResult& aRv);
+  Get(JSContext* aCx,
+      JS::Handle<JS::Value> aKey,
+      ErrorResult& aRv)
+  {
+    AssertIsOnOwningThread();
+
+    return GetInternal(/* aKeyOnly */ false, aCx, aKey, aRv);
+  }
+
+  already_AddRefed<IDBRequest>
+  GetKey(JSContext* aCx,
+         JS::Handle<JS::Value> aKey,
+         ErrorResult& aRv)
+  {
+    AssertIsOnOwningThread();
+
+    return GetInternal(/* aKeyOnly */ true, aCx, aKey, aRv);
+  }
 
   already_AddRefed<IDBRequest>
   Clear(JSContext* aCx, ErrorResult& aRv);
 
   already_AddRefed<IDBIndex>
   CreateIndex(const nsAString& aName,
               const StringOrStringSequence& aKeyPath,
               const IDBIndexParameters& aOptionalParameters,
@@ -329,16 +346,22 @@ private:
 
   already_AddRefed<IDBRequest>
   DeleteInternal(JSContext* aCx,
                  JS::Handle<JS::Value> aKey,
                  bool aFromCursor,
                  ErrorResult& aRv);
 
   already_AddRefed<IDBRequest>
+  GetInternal(bool aKeyOnly,
+              JSContext* aCx,
+              JS::Handle<JS::Value> aKey,
+              ErrorResult& aRv);
+
+  already_AddRefed<IDBRequest>
   GetAllInternal(bool aKeysOnly,
                  JSContext* aCx,
                  JS::Handle<JS::Value> aKey,
                  const Optional<uint32_t>& aLimit,
                  ErrorResult& aRv);
 
   already_AddRefed<IDBRequest>
   OpenCursorInternal(bool aKeysOnly,

--- a/dom/indexedDB/PBackgroundIDBRequest.ipdl
+++ b/dom/indexedDB/PBackgroundIDBRequest.ipdl
@@ -31,16 +31,21 @@ struct ObjectStorePutResponse
   Key key;
 };
 
 struct ObjectStoreGetResponse
 {
   SerializedStructuredCloneReadInfo cloneInfo;
 };
 
+struct ObjectStoreGetKeyResponse
+{
+  Key key;
+};
+
 struct ObjectStoreGetAllResponse
 {
   SerializedStructuredCloneReadInfo[] cloneInfos;
 };
 
 struct ObjectStoreGetAllKeysResponse
 {
   Key[] keys;
@@ -81,16 +86,17 @@ struct IndexCountResponse
 {
   uint64_t count;
 };
 
 union RequestResponse
 {
   nsresult;
   ObjectStoreGetResponse;
+  ObjectStoreGetKeyResponse;
   ObjectStoreAddResponse;
   ObjectStorePutResponse;
   ObjectStoreDeleteResponse;
   ObjectStoreClearResponse;
   ObjectStoreCountResponse;
   ObjectStoreGetAllResponse;
   ObjectStoreGetAllKeysResponse;
   IndexGetResponse;

--- a/dom/indexedDB/PBackgroundIDBSharedTypes.ipdlh
+++ b/dom/indexedDB/PBackgroundIDBSharedTypes.ipdlh
@@ -182,16 +182,22 @@ struct ObjectStorePutParams
 };
 
 struct ObjectStoreGetParams
 {
   int64_t objectStoreId;
   SerializedKeyRange keyRange;
 };
 
+struct ObjectStoreGetKeyParams
+{
+  int64_t objectStoreId;
+  SerializedKeyRange keyRange;
+};
+
 struct ObjectStoreGetAllParams
 {
   int64_t objectStoreId;
   OptionalKeyRange optionalKeyRange;
   uint32_t limit;
 };
 
 struct ObjectStoreGetAllKeysParams
@@ -255,16 +261,17 @@ struct IndexCountParams
   OptionalKeyRange optionalKeyRange;
 };
 
 union RequestParams
 {
   ObjectStoreAddParams;
   ObjectStorePutParams;
   ObjectStoreGetParams;
+  ObjectStoreGetKeyParams;
   ObjectStoreGetAllParams;
   ObjectStoreGetAllKeysParams;
   ObjectStoreDeleteParams;
   ObjectStoreClearParams;
   ObjectStoreCountParams;
   IndexGetParams;
   IndexGetKeyParams;
   IndexGetAllParams;

--- a/dom/webidl/IDBObjectStore.webidl
+++ b/dom/webidl/IDBObjectStore.webidl
@@ -32,16 +32,19 @@ interface IDBObjectStore {
 
     [Throws]
     IDBRequest delete (any key);
 
     [Throws]
     IDBRequest get (any key);
 
     [Throws]
+    IDBRequest getKey (any key);
+
+    [Throws]
     IDBRequest clear ();
 
     [Throws]
     IDBRequest openCursor (optional any range, optional IDBCursorDirection direction = "next");
 
     [Throws]
     IDBIndex   createIndex (DOMString name, (DOMString or sequence<DOMString>) keyPath, optional IDBIndexParameters optionalParameters);
 

--- a/testing/web-platform/meta/MANIFEST.json
+++ b/testing/web-platform/meta/MANIFEST.json
@@ -12201,16 +12201,24 @@
         "path": "IndexedDB/idbobjectstore_get7.htm",
         "url": "/IndexedDB/idbobjectstore_get7.htm"
       },
       {
         "path": "IndexedDB/idbobjectstore_getAll.html",
         "url": "/IndexedDB/idbobjectstore_getAll.html"
       },
       {
+        "path": "IndexedDB/idbobjectstore_getKey.htm",
+        "url": "/IndexedDB/idbobjectstore_getKey.htm"
+      },
+      {
+        "path": "IndexedDB/idbobjectstore_getKey_exception_order.htm",
+        "url": "/IndexedDB/idbobjectstore_getKey_exception_order.htm"
+      },
+      {
         "path": "IndexedDB/idbobjectstore_getAllKeys.html",
         "url": "/IndexedDB/idbobjectstore_getAllKeys.html"
       },
       {
         "path": "IndexedDB/idbobjectstore_index.htm",
         "url": "/IndexedDB/idbobjectstore_index.htm"
       },
       {

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/tests/IndexedDB/idbobjectstore_getKey.htm
@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>IDBObjectStore.getKey()</title>
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="http://w3c.github.io/IndexedDB/#dom-idbobjectstore-getkey">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="support.js"></script>
+
+<script>
+indexeddb_test(
+    function(t, db, txn) {
+        var os = db.createObjectStore("store");
+
+        for(var i = 3; i < 6; i++) {
+            os.add("data" + i, i);
+        }
+    },
+    function(t, db) {
+        var os = db.transaction("store").objectStore("store");
+        var req1 = os.getKey(IDBKeyRange.lowerBound(6));
+
+        req1.onerror = t.unreached_func('getKey request should succeed');
+        req1.onsuccess = t.step_func(function(e) {
+            assert_equals(e.target.result, undefined, "Record should not exist - lowerBound(6)");
+        });
+
+        var req2 = os.getKey(IDBKeyRange.upperBound(2));
+
+        req2.onerror = t.unreached_func('getKey request should succeed');
+        req2.onsuccess = t.step_func(function(e) {
+            assert_equals(e.target.result, undefined, "Record should not exist - upperBound(2)");
+            t.done();
+        });
+    },
+    "Attempt to retrieve a record that doesn't exist"
+);
+
+indexeddb_test(
+    function(t, db, txn) {
+        var os = db.createObjectStore("store");
+
+        for(var i = 3; i < 6; i++) {
+            os.add("data" + i, i);
+        }
+    },
+    function(t, db) {
+        var os = db.transaction("store").objectStore("store");
+        var req = os.getKey(IDBKeyRange.bound(0, 10));
+
+        req.onerror = t.unreached_func('getKey request should succeed');
+        req.onsuccess = t.step_func(function(e) {
+            assert_equals(e.target.result, 3, "getKey(0-10)");
+            t.done();
+        });
+    },
+    "Returns the first key in the range"
+);
+</script>
+
+<div id="log"></div>
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/tests/IndexedDB/idbobjectstore_getKey_exception_order.htm
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>IDBObjectStore.getKey() - Exception Orders</title>
+<link rel="author" title="Mozilla" href="https://www.mozilla.org">
+<link rel="help" href="http://w3c.github.io/IndexedDB/#dom-idbobjectstore-getkey">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="support.js"></script>
+
+<script>
+indexeddb_test(
+    function(t, db, txn) {
+        var deletedObjectStore = db.createObjectStore("s");
+        db.deleteObjectStore("s");
+        txn.oncomplete = function() {
+            assert_throws("InvalidStateError", function() {
+                deletedObjectStore.getKey(1);
+            }, "Deletion check should precede transaction-state check");
+            t.done();
+        };
+    },
+    null,
+    "InvalidStateError(Deleted ObjectStore) vs. TransactionInactiveError"
+);
+
+indexeddb_test(
+    function(t, db, txn) {
+        var store = db.createObjectStore("s");
+        txn.oncomplete = function() {
+            assert_throws("TransactionInactiveError", function() {
+                store.getKey(null);
+            }, "Transaction-state check should precede key range check");
+            t.done();
+        };
+    },
+    null,
+    "TransactionInactiveError vs. DataError"
+);
+
+indexeddb_test(
+    function(t, db, txn) {
+        var store = db.createObjectStore("s");
+        assert_throws("DataError", function() {
+            store.getKey(null);
+        }, "key range check");
+        t.done();
+    },
+    null,
+    "DataError"
+);
+</script>
+
+<div id="log"></div>

--- a/testing/web-platform/tests/IndexedDB/interfaces.idl
+++ b/testing/web-platform/tests/IndexedDB/interfaces.idl
@@ -93,16 +93,17 @@ interface IDBObjectStore {
     readonly    attribute any            keyPath;
     readonly    attribute DOMStringList  indexNames;
     readonly    attribute IDBTransaction transaction;
     readonly    attribute boolean        autoIncrement;
     IDBRequest put (any value, optional any key);
     IDBRequest add (any value, optional any key);
     IDBRequest delete (any key);
     IDBRequest get (any key);
+    IDBRequest getKey (any key);
     IDBRequest clear ();
     IDBRequest openCursor (optional any range, optional IDBCursorDirection direction = "next");
     IDBIndex   createIndex (DOMString name, (DOMString or sequence<DOMString>) keyPath, optional IDBIndexParameters optionalParameters);
     IDBIndex   index (DOMString name);
     void       deleteIndex (DOMString indexName);
     IDBRequest count (optional any key);
 };