diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2b4e1ee..54e6bd8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,8 @@ set_property(GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS TRUE)
 set(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-sSIDE_MODULE")
 set(CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS "-sSIDE_MODULE")
 add_compile_options(-fPIC -fexceptions)
+# createDefaultEventLoop is called by libFcitx5Utils.so but implemented in event_js.cpp.
+add_link_options(-sERROR_ON_UNDEFINED_SYMBOLS=0)
 
 set(PREBUILDER_LIB_DIR "${PROJECT_BINARY_DIR}/sysroot/usr/lib")
 set(PREBUILDER_SHARE_DIR "${PROJECT_BINARY_DIR}/sysroot/usr/share")
diff --git a/fcitx5 b/fcitx5
index 717034c..e2dcfcb 160000
--- a/fcitx5
+++ b/fcitx5
@@ -1 +1 @@
-Subproject commit 717034ced24ff6df23c2b1e82704b2f853ddc3f0
+Subproject commit e2dcfcbf3590dc42427b4537a9c1eeeef8d82743
diff --git a/fcitx5-webview b/fcitx5-webview
index 94aff6d..d994567 160000
--- a/fcitx5-webview
+++ b/fcitx5-webview
@@ -1 +1 @@
-Subproject commit 94aff6d4b759902e608f6bbdb3bcef1cb0f34e28
+Subproject commit d9945672a16dac4b003423ccb0818c246ab3fa42
diff --git a/patches/fcitx5.patch b/patches/fcitx5.patch
index f8110db..42dff47 100644
--- a/patches/fcitx5.patch
+++ b/patches/fcitx5.patch
@@ -1,16 +1,3 @@
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index aa90bad4..b4641520 100644
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -70,7 +70,7 @@ if (NOT TARGET Systemd::Systemd)
-         pkg_get_variable(DBUS_SYSTEM_BUS_DEFAULT_ADDRESS "dbus-1" "system_bus_default_address")
-     endif()
- 
--    if (NOT LIBUV_TARGET)
-+    if (NOT LIBUV_TARGET AND NOT EMSCRIPTEN)
-         if (NOT (TARGET PkgConfig::LibUV))
-             pkg_check_modules(LibUV REQUIRED IMPORTED_TARGET "libuv")
-         endif()
 diff --git a/src/lib/fcitx-config/CMakeLists.txt b/src/lib/fcitx-config/CMakeLists.txt
 index 85c9865b..3a995ca1 100644
 --- a/src/lib/fcitx-config/CMakeLists.txt
@@ -26,32 +13,10 @@ index 85c9865b..3a995ca1 100644
    )
  target_include_directories(Fcitx5Config PUBLIC
 diff --git a/src/lib/fcitx-utils/CMakeLists.txt b/src/lib/fcitx-utils/CMakeLists.txt
-index dd67e07d..21680660 100644
+index a1f18886..6f9a5832 100644
 --- a/src/lib/fcitx-utils/CMakeLists.txt
 +++ b/src/lib/fcitx-utils/CMakeLists.txt
-@@ -27,14 +27,18 @@ if (ENABLE_DBUS)
-     endif()
- endif()
- 
--if (NOT TARGET Systemd::Systemd)
-+if (TARGET Systemd::Systemd)
-   set(FCITX_UTILS_SOURCES
-     ${FCITX_UTILS_SOURCES}
--    event_libuv.cpp)
-+    event_sdevent.cpp)
-+elseif (EMSCRIPTEN)
-+  set(FCITX_UTILS_SOURCES
-+    ${FCITX_UTILS_SOURCES}
-+    event_js.cpp)
- else()
-   set(FCITX_UTILS_SOURCES
-     ${FCITX_UTILS_SOURCES}
--    event_sdevent.cpp)
-+    event_libuv.cpp)
- endif()
- 
- set(FCITX_UTILS_SOURCES
-@@ -121,8 +125,7 @@ ecm_setup_version(PROJECT
+@@ -119,8 +119,7 @@ ecm_setup_version(PROJECT
  
  add_library(Fcitx5Utils SHARED ${FCITX_UTILS_SOURCES})
  set_target_properties(Fcitx5Utils
@@ -61,160 +26,6 @@ index dd67e07d..21680660 100644
    EXPORT_NAME Utils
    )
  target_include_directories(Fcitx5Utils PUBLIC
-@@ -135,7 +138,7 @@ if(LIBKVM_FOUND)
- endif()
- 
- if (NOT TARGET Systemd::Systemd)
--    target_link_libraries(Fcitx5Utils PRIVATE ${LIBUV_TARGET})
-+    # target_link_libraries(Fcitx5Utils PRIVATE ${LIBUV_TARGET})
-     if (ENABLE_DBUS)
-         target_link_libraries(Fcitx5Utils PRIVATE PkgConfig::DBus)
-     endif()
-diff --git a/src/lib/fcitx-utils/event_js.cpp b/src/lib/fcitx-utils/event_js.cpp
-new file mode 100644
-index 00000000..68f7ee7f
---- /dev/null
-+++ b/src/lib/fcitx-utils/event_js.cpp
-@@ -0,0 +1,139 @@
-+#include <cassert>
-+#include <emscripten.h>
-+#include "event.h"
-+#include "log.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) {
-+        assert(clockid == CLOCK_MONOTONIC);
-+        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) {
-+    FCITX_D();
-+    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) {
-+    FCITX_D();
-+    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
 diff --git a/src/lib/fcitx/CMakeLists.txt b/src/lib/fcitx/CMakeLists.txt
 index df15dd57..36312bab 100644
 --- a/src/lib/fcitx/CMakeLists.txt
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 63ace5b..82da3e4 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -4,6 +4,7 @@ add_executable(Fcitx5
     input_method.cpp
     config.cpp
     action.cpp
+    event_js.cpp
 )
 
 target_include_directories(Fcitx5 PRIVATE
diff --git a/src/event_js.cpp b/src/event_js.cpp
new file mode 100644
index 0000000..3ffe746
--- /dev/null
+++ b/src/event_js.cpp
@@ -0,0 +1,121 @@
+#include "event_js.h"
+#include <emscripten.h>
+#include <fcitx-utils/event_p.h>
+#include <fcitx-utils/log.h>
+
+namespace fcitx {
+
+std::unique_ptr<EventLoopInterface> createDefaultEventLoop() {
+    return std::make_unique<JSEventLoop>();
+}
+
+const char *defaultEventLoopImplementation() { return "js"; }
+
+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());
+}
+
+std::unique_ptr<EventSourceIO>
+JSEventLoop::addIOEvent(int fd, IOEventFlags flags, IOCallback callback) {
+    auto source = std::make_unique<JSEventSourceIO>(std::move(callback));
+    return source;
+}
+
+std::unique_ptr<EventSourceTime>
+JSEventLoop::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> JSEventLoop::addExitEvent(EventCallback callback) {
+    auto source = std::make_unique<JSEventSource>(std::move(callback));
+    return source;
+}
+
+std::unique_ptr<EventSource>
+JSEventLoop::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> JSEventLoop::addPostEvent(EventCallback callback) {
+    FCITX_ERROR() << "Not implemented";
+    return nullptr;
+}
+
+} // namespace fcitx
diff --git a/src/event_js.h b/src/event_js.h
new file mode 100644
index 0000000..11d0007
--- /dev/null
+++ b/src/event_js.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <fcitx-utils/eventloopinterface.h>
+
+namespace fcitx {
+class JSEventLoop : public EventLoopInterface {
+  public:
+    JSEventLoop() = default;
+    ~JSEventLoop() override = default;
+    bool exec() override { return true; }
+    void exit() override {}
+    const char *implementation() const override { return "js"; }
+    void *nativeHandle() override { return nullptr; }
+
+    std::unique_ptr<EventSourceIO> addIOEvent(int fd, IOEventFlags flags,
+                                              IOCallback callback) override;
+    std::unique_ptr<EventSourceTime>
+    addTimeEvent(clockid_t clock, uint64_t usec, uint64_t accuracy,
+                 TimeCallback callback) override;
+    std::unique_ptr<EventSource> addExitEvent(EventCallback callback) override;
+    std::unique_ptr<EventSource> addDeferEvent(EventCallback callback) override;
+    std::unique_ptr<EventSource> addPostEvent(EventCallback callback) override;
+};
+} // namespace fcitx