diff --git a/src/plugins/platforms/wasm/qwasmwindow.cpp b/src/plugins/platforms/wasm/qwasmwindow.cpp
index 66c7593d145..85a2e252f11 100644
--- a/src/plugins/platforms/wasm/qwasmwindow.cpp
+++ b/src/plugins/platforms/wasm/qwasmwindow.cpp
@@ -106,99 +106,27 @@ QWasmWindow::QWasmWindow(QWindow *w, QWasmDeadKeySupport *deadKeySupport,
 
     m_flags = window()->flags();
 
-    const auto pointerCallback = std::function([this](emscripten::val event) {
-        const auto eventTypeString = event["type"].as<std::string>();
-
-        // Ideally it should not be happened but
-        // it takes place sometime with some reason
-        // without compositionend.
-        QWasmInputContext *wasmInput = QWasmIntegration::get()->wasmInputContext();
-        if (wasmInput && !wasmInput->preeditString().isEmpty())
-            wasmInput->commitPreeditAndClear();
-
-        if (processPointer(*PointerEvent::fromWeb(event)))
-            event.call<void>("preventDefault");
-    });
-
-    m_pointerEnterCallback =
-            std::make_unique<qstdweb::EventCallback>(m_qtWindow, "pointerenter", pointerCallback);
-    m_pointerLeaveCallback =
-            std::make_unique<qstdweb::EventCallback>(m_qtWindow, "pointerleave", pointerCallback);
-
-    m_wheelEventCallback = std::make_unique<qstdweb::EventCallback>(
-            m_qtWindow, "wheel", [this](emscripten::val event) {
-                if (processWheel(*WheelEvent::fromWeb(event)))
-                    event.call<void>("preventDefault");
-            });
-
-    const auto keyCallbackForInputContext = std::function([this](emscripten::val event) {
-        QWasmInputContext *wasmInput = QWasmIntegration::get()->wasmInputContext();
-        if (wasmInput) {
-            const auto keyString = QString::fromStdString(event["key"].as<std::string>());
-            qCDebug(qLcQpaWasmInputContext) << "Key callback" << keyString << keyString.size();
-
-            if (keyString == "Unidentified") {
-                // Android makes a bunch of KeyEvents as "Unidentified"
-                // They will be processed just in InputContext.
-                return;
-            } else if (event["ctrlKey"].as<bool>()
-                    || event["altKey"].as<bool>()
-                    || event["metaKey"].as<bool>()) {
-                if (processKeyForInputContext(*KeyEvent::fromWebWithDeadKeyTranslation(event, m_deadKeySupport)))
-                    event.call<void>("preventDefault");
-                event.call<void>("stopImmediatePropagation");
-                return;
-            } else if (keyString.size() != 1) {
-                if (!wasmInput->preeditString().isEmpty()) {
-                    if (keyString == "Process" || keyString == "Backspace") {
-                        // processed by InputContext
-                        // "Process" should be handled by InputContext but
-                        // QWasmInputContext's function is incomplete now
-                        // so, there will be some exceptions here.
-                        return;
-                    } else if (keyString != "Shift"
-                             && keyString != "Meta"
-                             && keyString != "Alt"
-                             && keyString != "Control"
-                             && !keyString.startsWith("Arrow")) {
-                        wasmInput->commitPreeditAndClear();
-                    }
-                }
-            } else if (wasmInput->inputMethodAccepted()) {
-                // processed in inputContext with skipping processKey
-                return;
-            }
-        }
-
-        qCDebug(qLcQpaWasmInputContext) << "processKey as KeyEvent";
-        if (processKeyForInputContext(*KeyEvent::fromWebWithDeadKeyTranslation(event, m_deadKeySupport)))
-            event.call<void>("preventDefault");
-        event.call<void>("stopImmediatePropagation");
-    });
-
-    const auto keyCallback = std::function([this](emscripten::val event) {
-        qCDebug(qLcQpaWasmInputContext) << "processKey as KeyEvent";
-        if (processKey(*KeyEvent::fromWebWithDeadKeyTranslation(event, m_deadKeySupport)))
-            event.call<void>("preventDefault");
-        event.call<void>("stopPropagation");
-    });
+    m_pointerEnterCallback = std::make_unique<qstdweb::EventCallback>(m_qtWindow, "pointerenter",
+        [this](emscripten::val event) { this->handlePointerEvent(event); });
+    m_pointerLeaveCallback = std::make_unique<qstdweb::EventCallback>(m_qtWindow, "pointerleave",
+        [this](emscripten::val event) { this->handlePointerEvent(event); });
+    m_wheelEventCallback = std::make_unique<qstdweb::EventCallback>( m_qtWindow, "wheel",
+        [this](emscripten::val event) { this->handleWheelEvent(event); });
 
     QWasmInputContext *wasmInput = QWasmIntegration::get()->wasmInputContext();
     if (wasmInput) {
         m_keyDownCallbackForInputContext =
-            std::make_unique<qstdweb::EventCallback>(wasmInput->m_inputElement,
-                                                     "keydown",
-                                                     keyCallbackForInputContext);
+            std::make_unique<qstdweb::EventCallback>(wasmInput->m_inputElement, "keydown",
+            [this](emscripten::val event) { this->handleKeyForInputContextEvent(event); });
         m_keyUpCallbackForInputContext =
-            std::make_unique<qstdweb::EventCallback>(wasmInput->m_inputElement,
-                                                     "keyup",
-                                                     keyCallbackForInputContext);
+            std::make_unique<qstdweb::EventCallback>(wasmInput->m_inputElement, "keyup",
+            [this](emscripten::val event) { this->handleKeyForInputContextEvent(event); });
     }
 
-    m_keyDownCallback =
-            std::make_unique<qstdweb::EventCallback>(m_qtWindow, "keydown", keyCallback);
-    m_keyUpCallback =std::make_unique<qstdweb::EventCallback>(m_qtWindow, "keyup", keyCallback);
-
+    m_keyDownCallback = std::make_unique<qstdweb::EventCallback>(m_qtWindow, "keydown",
+        [this](emscripten::val event) { this->handleKeyEvent(event); });
+    m_keyUpCallback =std::make_unique<qstdweb::EventCallback>(m_qtWindow, "keyup",
+        [this](emscripten::val event) { this->handleKeyEvent(event); });
 
     setParent(parent());
 }
@@ -544,6 +472,14 @@ void QWasmWindow::commitParent(QWasmWindowTreeNode *parent)
     m_commitedParent = parent;
 }
 
+void QWasmWindow::handleKeyEvent(const emscripten::val &event)
+{
+    qCDebug(qLcQpaWasmInputContext) << "processKey as KeyEvent";
+    if (processKey(*KeyEvent::fromWebWithDeadKeyTranslation(event, m_deadKeySupport)))
+        event.call<void>("preventDefault");
+    event.call<void>("stopPropagation");
+}
+
 bool QWasmWindow::processKey(const KeyEvent &event)
 {
     constexpr bool ProceedToNativeEvent = false;
@@ -564,6 +500,52 @@ bool QWasmWindow::processKey(const KeyEvent &event)
             : result;
 }
 
+void QWasmWindow::handleKeyForInputContextEvent(const emscripten::val &event)
+{
+    QWasmInputContext *wasmInput = QWasmIntegration::get()->wasmInputContext();
+    if (wasmInput) {
+        const auto keyString = QString::fromStdString(event["key"].as<std::string>());
+        qCDebug(qLcQpaWasmInputContext) << "Key callback" << keyString << keyString.size();
+
+        if (keyString == "Unidentified") {
+            // Android makes a bunch of KeyEvents as "Unidentified"
+            // They will be processed just in InputContext.
+            return;
+        } else if (event["ctrlKey"].as<bool>()
+                || event["altKey"].as<bool>()
+                || event["metaKey"].as<bool>()) {
+            if (processKeyForInputContext(*KeyEvent::fromWebWithDeadKeyTranslation(event, m_deadKeySupport)))
+                event.call<void>("preventDefault");
+            event.call<void>("stopImmediatePropagation");
+            return;
+        } else if (keyString.size() != 1) {
+            if (!wasmInput->preeditString().isEmpty()) {
+                if (keyString == "Process" || keyString == "Backspace") {
+                    // processed by InputContext
+                    // "Process" should be handled by InputContext but
+                    // QWasmInputContext's function is incomplete now
+                    // so, there will be some exceptions here.
+                    return;
+                } else if (keyString != "Shift"
+                         && keyString != "Meta"
+                         && keyString != "Alt"
+                         && keyString != "Control"
+                         && !keyString.startsWith("Arrow")) {
+                    wasmInput->commitPreeditAndClear();
+                }
+            }
+        } else if (wasmInput->inputMethodAccepted()) {
+            // processed in inputContext with skipping processKey
+            return;
+        }
+    }
+
+    qCDebug(qLcQpaWasmInputContext) << "processKey as KeyEvent";
+    if (processKeyForInputContext(*KeyEvent::fromWebWithDeadKeyTranslation(event, m_deadKeySupport)))
+        event.call<void>("preventDefault");
+    event.call<void>("stopImmediatePropagation");
+}
+
 bool QWasmWindow::processKeyForInputContext(const KeyEvent &event)
 {
     qCDebug(qLcQpaWasmInputContext) << Q_FUNC_INFO;
@@ -587,6 +569,19 @@ bool QWasmWindow::processKeyForInputContext(const KeyEvent &event)
     return result;
 }
 
+void QWasmWindow::handlePointerEvent(const emscripten::val &event)
+{
+    // Ideally it should not be happened but
+    // it takes place sometime with some reason
+    // without compositionend.
+    QWasmInputContext *wasmInput = QWasmIntegration::get()->wasmInputContext();
+    if (wasmInput && !wasmInput->preeditString().isEmpty())
+        wasmInput->commitPreeditAndClear();
+
+    if (processPointer(*PointerEvent::fromWeb(event)))
+        event.call<void>("preventDefault");
+}
+
 bool QWasmWindow::processPointer(const PointerEvent &event)
 {
     if (event.pointerType != PointerType::Mouse && event.pointerType != PointerType::Pen)
@@ -610,6 +605,12 @@ bool QWasmWindow::processPointer(const PointerEvent &event)
     return false;
 }
 
+void QWasmWindow::handleWheelEvent(const emscripten::val &event)
+{
+    if (processWheel(*WheelEvent::fromWeb(event)))
+        event.call<void>("preventDefault");
+}
+
 bool QWasmWindow::processWheel(const WheelEvent &event)
 {
     // Web scroll deltas are inverted from Qt deltas - negate.
diff --git a/src/plugins/platforms/wasm/qwasmwindow.h b/src/plugins/platforms/wasm/qwasmwindow.h
index 480ad6de721..9e259e58f68 100644
--- a/src/plugins/platforms/wasm/qwasmwindow.h
+++ b/src/plugins/platforms/wasm/qwasmwindow.h
@@ -123,9 +123,13 @@ private:
     void applyWindowState();
     void commitParent(QWasmWindowTreeNode *parent);
 
+    void handleKeyEvent(const emscripten::val &event);
     bool processKey(const KeyEvent &event);
+    void handleKeyForInputContextEvent(const emscripten::val &event);
     bool processKeyForInputContext(const KeyEvent &event);
+    void handlePointerEvent(const emscripten::val &event);
     bool processPointer(const PointerEvent &event);
+    void handleWheelEvent(const emscripten::val &event);
     bool processWheel(const WheelEvent &event);
 
     QWindow *m_window = nullptr;