diff --git a/demo/starter/slides.md b/demo/starter/slides.md
index 9e65e48145..e6c3a1a7da 100644
--- a/demo/starter/slides.md
+++ b/demo/starter/slides.md
@@ -45,6 +45,7 @@ The last comment block of each slide will be treated as slide notes. It will be
 
 ---
 transition: fade-out
+split: 30
 ---
 
 # What is Slidev?
@@ -87,6 +88,7 @@ Here is another comment.
 ---
 transition: slide-up
 level: 2
+split: 60
 ---
 
 # Navigation
diff --git a/packages/client/composables/useNav.ts b/packages/client/composables/useNav.ts
index e1500c42a4..1cf03a09b2 100644
--- a/packages/client/composables/useNav.ts
+++ b/packages/client/composables/useNav.ts
@@ -5,7 +5,7 @@ import { slides } from '#slidev/slides'
 import { clamp } from '@antfu/utils'
 import { parseRangeString } from '@slidev/parser/utils'
 import { createSharedComposable } from '@vueuse/core'
-import { computed, ref, watch } from 'vue'
+import { computed, ref, toRaw, watch } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { CLICKS_MAX } from '../constants'
 import { configs } from '../env'
@@ -292,6 +292,16 @@ const useNavState = createSharedComposable((): SlidevContextNavState => {
   const currentSlideRoute = computed(() => slides.value[currentSlideNo.value - 1])
   const printRange = ref(parseRangeString(slides.value.length, currentRoute?.query?.range as string | undefined))
 
+  watch(currentSlideRoute, () => {
+    window.dispatchEvent(new CustomEvent('slidev-slide-changed', {
+      detail: {
+        slideNumber: currentSlideNo.value,
+        slide: toRaw(currentSlideRoute.value?.meta.slide),
+        frontmatter: toRaw(currentSlideRoute.value?.meta.slide.frontmatter),
+      },
+    }))
+  })
+
   const queryClicksRaw = useRouteQuery<string>('clicks', '0')
 
   const clicksContext = computed(() => getPrimaryClicks(currentSlideRoute.value))
diff --git a/packages/client/pages/presenter.vue b/packages/client/pages/presenter.vue
index 0ad2ae3075..6e9b5898aa 100644
--- a/packages/client/pages/presenter.vue
+++ b/packages/client/pages/presenter.vue
@@ -88,6 +88,21 @@ const SideEditor = shallowRef<any>()
 if (__DEV__ && __SLIDEV_FEATURE_EDITOR__)
   import('../internals/SideEditor.vue').then(v => SideEditor.value = v.default)
 
+function parseTimerString(timeString: string) {
+  const [seconds, minutes = 0, hours = 0] = timeString.split(':').toReversed().map(n => Number.parseInt(n, 10))
+  return hours * 3600 + minutes * 60 + seconds
+}
+
+window.addEventListener('slidev-slide-changed', (e) => {
+  const timerCounter = parseTimerString(timer.value)
+  const splitCounter = typeof (e as CustomEvent).detail.frontmatter.split === 'string' ? parseTimerString((e as CustomEvent).detail.frontmatter.split) : (e as CustomEvent).detail.frontmatter.split || 0
+
+  if (splitCounter) {
+    const delta = timerCounter - splitCounter
+    console.warn('delta', delta)
+  }
+})
+
 // sync presenter cursor
 onMounted(() => {
   const slidesContainer = main.value!.querySelector('#slide-content')!