4 files changed, 26 insertions, 1 deletions
diff --git a/components/script/dom/globalscope.rs b/components/script/dom/globalscope.rs
index 04f8d948a24..e551009b59d 100644
--- a/components/script/dom/globalscope.rs
+++ b/components/script/dom/globalscope.rs
@@ -4,6 +4,7 @@
 
 use crate::dom::bindings::cell::DomRefCell;
 use crate::dom::bindings::codegen::Bindings::EventSourceBinding::EventSourceBinding::EventSourceMethods;
+use crate::dom::bindings::codegen::Bindings::VoidFunctionBinding::VoidFunction;
 use crate::dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use crate::dom::bindings::codegen::Bindings::WorkerGlobalScopeBinding::WorkerGlobalScopeMethods;
 use crate::dom::bindings::conversions::{root_from_object, root_from_object_static};
@@ -32,7 +33,7 @@ use crate::dom::performance::Performance;
 use crate::dom::window::Window;
 use crate::dom::workerglobalscope::WorkerGlobalScope;
 use crate::dom::workletglobalscope::WorkletGlobalScope;
-use crate::microtask::{Microtask, MicrotaskQueue};
+use crate::microtask::{Microtask, MicrotaskQueue, UserMicrotask};
 use crate::script_module::ModuleTree;
 use crate::script_runtime::{CommonScriptMsg, JSContext as SafeJSContext, ScriptChan, ScriptPort};
 use crate::script_thread::{MainThreadScriptChan, ScriptThread};
@@ -1772,6 +1773,13 @@ impl GlobalScope {
         self.timers.clear_timeout_or_interval(self, handle);
     }
 
+    pub fn queue_function_as_microtask(&self, callback: Rc<VoidFunction>) {
+        self.enqueue_microtask(Microtask::User(UserMicrotask {
+            callback: callback,
+            pipeline: self.pipeline_id(),
+        }))
+    }
+
     pub fn fire_timer(&self, handle: TimerEventId) {
         self.timers.fire_timer(handle, self);
     }
diff --git a/components/script/dom/webidls/WindowOrWorkerGlobalScope.webidl b/components/script/dom/webidls/WindowOrWorkerGlobalScope.webidl
index c798b56ab00..61f150f8e81 100644
--- a/components/script/dom/webidls/WindowOrWorkerGlobalScope.webidl
+++ b/components/script/dom/webidls/WindowOrWorkerGlobalScope.webidl
@@ -20,6 +20,9 @@ interface mixin WindowOrWorkerGlobalScope {
   long setInterval(TimerHandler handler, optional long timeout = 0, any... arguments);
   void clearInterval(optional long handle = 0);
 
+  // microtask queuing
+  void queueMicrotask(VoidFunction callback);
+
   // ImageBitmap
   // Promise<ImageBitmap> createImageBitmap(ImageBitmapSource image, optional ImageBitmapOptions options);
   // Promise<ImageBitmap> createImageBitmap(
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index d48f16ea662..80fa021346c 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -11,6 +11,7 @@ use crate::dom::bindings::codegen::Bindings::HistoryBinding::HistoryBinding::His
 use crate::dom::bindings::codegen::Bindings::MediaQueryListBinding::MediaQueryListBinding::MediaQueryListMethods;
 use crate::dom::bindings::codegen::Bindings::PermissionStatusBinding::PermissionState;
 use crate::dom::bindings::codegen::Bindings::RequestBinding::RequestInit;
+use crate::dom::bindings::codegen::Bindings::VoidFunctionBinding::VoidFunction;
 use crate::dom::bindings::codegen::Bindings::WindowBinding::{
     self, FrameRequestCallback, WindowMethods, WindowPostMessageOptions,
 };
@@ -871,6 +872,12 @@ impl WindowMethods for Window {
         self.ClearTimeout(handle);
     }
 
+    // https://html.spec.whatwg.org/multipage/#dom-queuemicrotask
+    fn QueueMicrotask(&self, callback: Rc<VoidFunction>) {
+        self.upcast::<GlobalScope>()
+            .queue_function_as_microtask(callback);
+    }
+
     // https://html.spec.whatwg.org/multipage/#dom-window
     fn Window(&self) -> DomRoot<WindowProxy> {
         self.window_proxy()
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index f29fd70f99f..0b8d7e33478 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -5,6 +5,7 @@
 use crate::compartments::InCompartment;
 use crate::dom::bindings::cell::{DomRefCell, Ref};
 use crate::dom::bindings::codegen::Bindings::RequestBinding::RequestInit;
+use crate::dom::bindings::codegen::Bindings::VoidFunctionBinding::VoidFunction;
 use crate::dom::bindings::codegen::Bindings::WorkerBinding::WorkerType;
 use crate::dom::bindings::codegen::Bindings::WorkerGlobalScopeBinding::WorkerGlobalScopeMethods;
 use crate::dom::bindings::codegen::UnionTypes::{RequestOrUSVString, StringOrFunction};
@@ -341,6 +342,12 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
         self.ClearTimeout(handle);
     }
 
+    // https://html.spec.whatwg.org/multipage/#dom-queuemicrotask
+    fn QueueMicrotask(&self, callback: Rc<VoidFunction>) {
+        self.upcast::<GlobalScope>()
+            .queue_function_as_microtask(callback);
+    }
+
     #[allow(unrooted_must_root)]
     // https://fetch.spec.whatwg.org/#fetch-method
     fn Fetch(