diff --git a/src/lib/fcitx-utils/event_js.cpp b/src/lib/fcitx-utils/event_js.cpp
new file mode 100644
index 000000000..522f6d99a
--- /dev/null
+++ b/src/lib/fcitx-utils/event_js.cpp
@@ -0,0 +1,134 @@
+#include <emscripten.h>
+#include "event.h"
+
+namespace fcitx {
+
+template <typename Interface>
+struct JSEventSourceBase : public Interface {
+public:
+    ~JSEventSourceBase() override {}
+
+    bool isEnabled() const override { return enabled_; }
+
+    void setEnabled(bool enabled) override { enabled_ = enabled; }
+
+    bool isOneShot() const override { return oneShot_; }
+
+    void setOneShot() override { oneShot_ = true; }
+
+private:
+    bool enabled_ = false;
+    bool oneShot_ = false;
+};
+
+struct JSEventSource : public JSEventSourceBase<EventSource> {
+    JSEventSource(EventCallback _callback)
+        : callback_(std::make_shared<EventCallback>(std::move(_callback))) {}
+
+    std::shared_ptr<EventCallback> callback_;
+};
+
+struct JSEventSourceIO : public JSEventSourceBase<EventSourceIO> {
+    JSEventSourceIO(IOCallback _callback) {}
+
+    int fd() const override { return 0; }
+
+    void setFd(int fd) override {}
+
+    IOEventFlags events() const override { return IOEventFlag::In; }
+
+    void setEvents(IOEventFlags flags) override {}
+
+    IOEventFlags revents() const override { return IOEventFlag::In; }
+};
+
+void TimeEventCallback(void *arg);
+
+struct JSEventSourceTime : public JSEventSourceBase<EventSourceTime> {
+    JSEventSourceTime(TimeCallback _callback, uint64_t time, clockid_t clockid)
+        : callback_(std::make_shared<TimeCallback>(std::move(_callback))),
+          time_(time), clockid_(clockid) {
+        setOneShot();
+    }
+
+    void setOneShot() override {
+        int t = std::max<int64_t>(0, time_ - now(CLOCK_MONOTONIC)) / 1000;
+        emscripten_async_call(TimeEventCallback, this, t);
+    }
+
+    uint64_t time() const override { return time_; }
+
+    void setTime(uint64_t time) override { time_ = time; }
+
+    uint64_t accuracy() const override { return 0; }
+
+    void setAccuracy(uint64_t time) override {}
+
+    clockid_t clock() const override { return clockid_; }
+
+    std::shared_ptr<TimeCallback> callback_;
+
+private:
+    uint64_t time_;
+    clockid_t clockid_;
+};
+
+void TimeEventCallback(void *arg) {
+    auto source = static_cast<JSEventSourceTime *>(arg);
+    (*source->callback_)(source, source->time());
+}
+
+class EventLoopPrivate {
+public:
+    EventLoopPrivate() {}
+
+    ~EventLoopPrivate() {}
+};
+
+EventLoop::EventLoop() : d_ptr(std::make_unique<EventLoopPrivate>()) {}
+
+EventLoop::~EventLoop() = default;
+
+const char *EventLoop::impl() { return "js-event"; }
+
+void *EventLoop::nativeHandle() { return nullptr; }
+
+bool EventLoop::exec() { return true; }
+
+void EventLoop::exit() {}
+
+std::unique_ptr<EventSourceIO> EventLoop::addIOEvent(int fd, IOEventFlags flags,
+                                                     IOCallback callback) {
+    auto source = std::make_unique<JSEventSourceIO>(std::move(callback));
+    return source;
+}
+
+std::unique_ptr<EventSourceTime>
+EventLoop::addTimeEvent(clockid_t clock, uint64_t usec, uint64_t accuracy,
+                        TimeCallback callback) {
+    auto source =
+        std::make_unique<JSEventSourceTime>(std::move(callback), usec, clock);
+    return source;
+}
+
+std::unique_ptr<EventSource> EventLoop::addExitEvent(EventCallback callback) {
+    auto source = std::make_unique<JSEventSource>(std::move(callback));
+    return source;
+}
+
+std::unique_ptr<EventSource> EventLoop::addDeferEvent(EventCallback callback) {
+    return addTimeEvent(
+        CLOCK_MONOTONIC, now(CLOCK_MONOTONIC), 0,
+        [callback = std::move(callback)](EventSourceTime *source, uint64_t) {
+            return callback(source);
+        });
+}
+
+std::unique_ptr<EventSource> EventLoop::addPostEvent(EventCallback callback) {
+    return addTimeEvent(
+        CLOCK_MONOTONIC, now(CLOCK_MONOTONIC), 0,
+        [callback = std::move(callback)](EventSourceTime *source, uint64_t) {
+            return callback(source);
+        });
+}
+} // namespace fcitx