diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index d89aefdb..cca5ae69 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -3019,6 +3019,14 @@ Volt:
   tm_scope: source.d
   ace_mode: d
 
+WebIDL:
+  type: programming
+  extensions:
+  - .webidl
+  tm_scope: none
+  ace_mode: none
+
+
 XC:
   type: programming
   extensions:
diff --git a/samples/WebIDL/AnimationEvent.webidl b/samples/WebIDL/AnimationEvent.webidl
new file mode 100644
index 00000000..e48ed571
--- /dev/null
+++ b/samples/WebIDL/AnimationEvent.webidl
@@ -0,0 +1,25 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * http://www.w3.org/TR/css3-animations/#animation-events-
+ * http://dev.w3.org/csswg/css3-animations/#animation-events-
+ *
+ * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+[Constructor(DOMString type, optional AnimationEventInit eventInitDict)]
+interface AnimationEvent : Event {
+  readonly attribute DOMString animationName;
+  readonly attribute float     elapsedTime;
+  readonly attribute DOMString pseudoElement;
+};
+
+dictionary AnimationEventInit : EventInit {
+  DOMString animationName = "";
+  float elapsedTime = 0;
+  DOMString pseudoElement = "";
+};
diff --git a/samples/WebIDL/Fetch.webidl b/samples/WebIDL/Fetch.webidl
new file mode 100644
index 00000000..fb022126
--- /dev/null
+++ b/samples/WebIDL/Fetch.webidl
@@ -0,0 +1,35 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is
+ * http://fetch.spec.whatwg.org/
+ */
+
+typedef object JSON;
+// FIXME(nsm): Bug 739173: FormData is not available in workers.
+// typedef (ArrayBuffer or ArrayBufferView or Blob or FormData or USVString or URLSearchParams) BodyInit;
+typedef (ArrayBuffer or ArrayBufferView or Blob or USVString or URLSearchParams) BodyInit;
+
+[NoInterfaceObject, Exposed=(Window,Worker)]
+interface Body {
+  readonly attribute boolean bodyUsed;
+  [Throws]
+  Promise<ArrayBuffer> arrayBuffer();
+  [Throws]
+  Promise<Blob> blob();
+  // FIXME(nsm): Bug 739173 FormData is not supported in workers.
+  // Promise<FormData> formData();
+  [Throws]
+  Promise<JSON> json();
+  [Throws]
+  Promise<USVString> text();
+};
+
+[NoInterfaceObject, Exposed=(Window,Worker)]
+interface GlobalFetch {
+  [Throws, Func="mozilla::dom::Headers::PrefEnabled"]
+  Promise<Response> fetch(RequestInfo input, optional RequestInit init);
+};
+