diff --git a/README.md b/README.md
index b1543ba..ade7d27 100644
--- a/README.md
+++ b/README.md
@@ -78,9 +78,11 @@ If both `menu.dll` and `menu.lua` exists in scripts folder, one of it may be nam
 
 - `max_title_length=80`: Limits the title length in dynamic submenu, set to 0 to disable.
 
-## Updating menu from script
+## Scripting
 
-The menu data is stored in `user-data/menu/items` property with the following structure:
+### Properties
+
+#### `user-data/menu/items`
 
 ```
 MPV_FORMAT_NODE_ARRAY
@@ -92,10 +94,44 @@ MPV_FORMAT_NODE_ARRAY
      "submenu"        MPV_FORMAT_NODE_ARRAY[menu item]         (required if type is submenu)
 ```
 
-Updating this property will trigger an update of the menu UI.
+The menu data of the C plugin is stored in this property, updating it will trigger an update of the menu UI.
 
 To reduce update frequency, it's recommended to update this property in [mp.register_idle(fn)](https://mpv.io/manual/master/#lua-scripting-mp-register-idle(fn)).
 
+Be aware that `dyn_menu.lua` is conflict with other scripts that also update the `user-data/menu/items` property,
+you may use the messages below if you only want to update part of the menu.
+
+### Messages
+
+#### `menu-ready`
+
+Broadcasted when `dyn_menu.lua` has initilized itself.
+
+#### `get <keyword> <src>`
+
+Get the menu item structure of `keyword`, and send a json reply to `src`.
+
+```json
+{
+  "keyword": "chapters"
+  "item": {
+    "title": "Chapters",
+    "type": "submenu",
+    "submenu": []
+  }
+}
+```
+
+The reply is sent via `srcript-message-to <src> menu-get-reply <json>`.
+
+If `keyword` is not found, the result json will contain an additional `error` field, and no `item` field.
+
+#### `update <keyword> <json>`
+
+Update the menu item structure of `keyword` with `json`.
+
+As a convenience, if you don't want to override menu title and type, omit the corresponding field in `json`.
+
 ## Credits
 
 This project contains code copied from [mpv](https://github.com/mpv-player/mpv).
diff --git a/lua/dyn_menu.lua b/lua/dyn_menu.lua
index 85e0a0a..154dbe5 100644
--- a/lua/dyn_menu.lua
+++ b/lua/dyn_menu.lua
@@ -1,26 +1,9 @@
 -- Copyright (c) 2023 tsl0922. All rights reserved.
 -- SPDX-License-Identifier: GPL-2.0-only
---
--- #@keyword support for dynamic menu
---
--- supported keywords:
---
---   #@tracks               video/audio/sub tracks
---   #@tracks/video         video track list
---   #@tracks/audio         audio track list
---   #@tracks/sub           subtitle list
---   #@tracks/sub-secondary subtitle list (secondary)
---   #@chapters             chapter list
---   #@editions             edition list
---   #@audio-devices        audio device list
---   #@playlist             playlist
---   #@profiles             profile list
---
---   #@prop:check           check menu item if property is true
---   #@prop:check!          check menu item if property is false
 
 local opts = require('mp.options')
 local utils = require('mp.utils')
+local msg = require('mp.msg')
 
 -- user options
 local o = {
@@ -31,6 +14,7 @@ opts.read_options(o)
 local menu_prop = 'user-data/menu/items'
 local menu_items = mp.get_property_native(menu_prop, {})
 local menu_items_dirty = false
+local dyn_menus = {}
 
 -- escape codec name to make it more readable
 local function escape_codec(str)
@@ -157,11 +141,16 @@ local function to_submenu(item)
     return item.submenu
 end
 
+local function observe_property(menu, prop, type, fn)
+    mp.observe_property(prop, type, fn)
+    menu.fns[#menu.fns + 1] = fn
+end
+
 -- handle #@tracks menu update
-local function update_tracks_menu(item)
-    local submenu = to_submenu(item)
+local function update_tracks_menu(menu)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('track-list', 'native', function(_, track_list)
+    local function track_list_cb(_, track_list)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not track_list or #track_list == 0 then return end
@@ -176,28 +165,32 @@ local function update_tracks_menu(item)
         for _, item in ipairs(items_a) do table.insert(submenu, item) end
         if #submenu > 0 and #items_s > 0 then table.insert(submenu, { type = 'separator' }) end
         for _, item in ipairs(items_s) do table.insert(submenu, item) end
-    end)
+    end
+
+    observe_property(menu, 'track-list', 'native', track_list_cb)
 end
 
 -- handle #@tracks/<type> menu update for given type
-local function update_track_menu(item, type, prop)
-    local submenu = to_submenu(item)
+local function update_track_menu(menu, type, prop)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('track-list', 'native', function(_, track_list)
+    local function track_list_cb(_, track_list)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not track_list or #track_list == 0 then return end
 
         local items = build_track_items(track_list, type, prop, false)
         for _, item in ipairs(items) do table.insert(submenu, item) end
-    end)
+    end
+
+    observe_property(menu, 'track-list', 'native', track_list_cb)
 end
 
 -- handle #@chapters menu update
-local function update_chapters_menu(item)
-    local submenu = to_submenu(item)
+local function update_chapters_menu(menu)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('chapter-list', 'native', function(_, chapter_list)
+    local function chapter_list_cb(_, chapter_list)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not chapter_list or #chapter_list == 0 then return end
@@ -214,22 +207,25 @@ local function update_chapters_menu(item)
                 state = id == pos + 1 and { 'checked' } or {},
             }
         end
-    end)
+    end
 
-    mp.observe_property('chapter', 'number', function(_, pos)
+    local function chapter_cb(_, pos)
         if not pos then pos = -1 end
         for id, item in ipairs(submenu) do
             item.state = id == pos + 1 and { 'checked' } or {}
         end
         menu_items_dirty = true
-    end)
+    end
+
+    observe_property(menu, 'chapter-list', 'native', chapter_list_cb)
+    observe_property(menu, 'chapter', 'number', chapter_cb)
 end
 
 -- handle #@edition menu update
-local function update_editions_menu(item)
-    local submenu = to_submenu(item)
+local function update_editions_menu(menu)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('edition-list', 'native', function(_, edition_list)
+    local function edition_list_cb(_, edition_list)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not edition_list or #edition_list == 0 then return end
@@ -245,22 +241,25 @@ local function update_editions_menu(item)
                 state = id == current + 1 and { 'checked' } or {},
             }
         end
-    end)
+    end
 
-    mp.observe_property('current-edition', 'number', function(_, pos)
+    local function edition_cb(_, pos)
         if not pos then pos = -1 end
         for id, item in ipairs(submenu) do
             item.state = id == pos + 1 and { 'checked' } or {}
         end
         menu_items_dirty = true
-    end)
+    end
+
+    observe_property(menu, 'edition-list', 'native', edition_list_cb)
+    observe_property(menu, 'current-edition', 'number', edition_cb)
 end
 
 -- handle #@audio-devices menu update
-local function update_audio_devices_menu(item)
-    local submenu = to_submenu(item)
+local function update_audio_devices_menu(menu)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('audio-device-list', 'native', function(_, device_list)
+    local function device_list_cb(_, device_list)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not device_list or #device_list == 0 then return end
@@ -273,15 +272,18 @@ local function update_audio_devices_menu(item)
                 state = device.name == current and { 'checked' } or {},
             }
         end
-    end)
+    end
 
-    mp.observe_property('audio-device', 'string', function(_, name)
-        if not name then name = '' end
+    local function device_cb(_, device)
+        if not device then device = '' end
         for _, item in ipairs(submenu) do
-            item.state = item.cmd:match('%s*set audio%-device%s+(%S+)%s*$') == name and { 'checked' } or {}
+            item.state = item.cmd:match('%s*set audio%-device%s+(%S+)%s*$') == device and { 'checked' } or {}
         end
         menu_items_dirty = true
-    end)
+    end
+
+    observe_property(menu, 'audio-device-list', 'native', device_list_cb)
+    observe_property(menu, 'audio-device', 'string', device_cb)
 end
 
 -- build playlist item title
@@ -299,10 +301,10 @@ local function build_playlist_title(item, id)
 end
 
 -- handle #@playlist menu update
-local function update_playlist_menu(item)
-    local submenu = to_submenu(item)
+local function update_playlist_menu(menu)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('playlist', 'native', function(_, playlist)
+    local function playlist_cb(_, playlist)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not playlist or #playlist == 0 then return end
@@ -314,14 +316,16 @@ local function update_playlist_menu(item)
                 state = item.current and { 'checked' } or {},
             }
         end
-    end)
+    end
+
+    observe_property(menu, 'playlist', 'native', playlist_cb)
 end
 
 -- handle #@profiles menu update
-local function update_profiles_menu(item)
-    local submenu = to_submenu(item)
+local function update_profiles_menu(menu)
+    local submenu = to_submenu(menu.item)
 
-    mp.observe_property('profile-list', 'native', function(_, profile_list)
+    local function profile_list_cb(_, profile_list)
         for i = #submenu, 1, -1 do table.remove(submenu, i) end
         menu_items_dirty = true
         if not profile_list or #profile_list == 0 then return end
@@ -335,11 +339,14 @@ local function update_profiles_menu(item)
                 }
             end
         end
-    end)
+    end
+
+    observe_property(menu, 'profile-list', 'native', profile_list_cb)
 end
 
 -- handle #@prop:check
-function update_check_status(item, keyword)
+function update_check_status(menu, keyword)
+    local item = menu.item
     local prop, e = keyword:match('^([%w-]+):check(!?)$')
     if not prop then return false end
 
@@ -351,40 +358,49 @@ function update_check_status(item, keyword)
         if tp == 'table' then return #v > 0 end
         return v ~= nil
     end
-    mp.observe_property(prop, 'native', function(name, value)
+
+    local function prop_cb(_, value)
         local ok = check(value)
         if e == '!' then ok = not ok end
         item.state = ok and { 'checked' } or {}
         menu_items_dirty = true
-    end)
+    end
+
+    observe_property(menu, prop, 'native', prop_cb)
 
     return true
 end
 
 -- update dynamic menu item and handle update
 local function dyn_menu_update(item, keyword)
-    if update_check_status(item, keyword) then return end
+    local menu = {
+        item = item,
+        fns = {},
+    }
+    dyn_menus[keyword] = menu
+
+    if update_check_status(menu, keyword) then return end
 
     if keyword == 'tracks' then
-        update_tracks_menu(item)
+        update_tracks_menu(menu)
     elseif keyword == 'tracks/video' then
-        update_track_menu(item, "video", "vid")
+        update_track_menu(menu, "video", "vid")
     elseif keyword == 'tracks/audio' then
-        update_track_menu(item, "audio", "aid")
+        update_track_menu(menu, "audio", "aid")
     elseif keyword == 'tracks/sub' then
-        update_track_menu(item, "sub", "sid")
+        update_track_menu(menu, "sub", "sid")
     elseif keyword == 'tracks/sub-secondary' then
-        update_track_menu(item, "sub", "secondary-sid")
+        update_track_menu(menu, "sub", "secondary-sid")
     elseif keyword == 'chapters' then
-        update_chapters_menu(item)
+        update_chapters_menu(menu)
     elseif keyword == 'editions' then
-        update_editions_menu(item)
+        update_editions_menu(menu)
     elseif keyword == 'audio-devices' then
-        update_audio_devices_menu(item)
+        update_audio_devices_menu(menu)
     elseif keyword == 'playlist' then
-        update_playlist_menu(item)
+        update_playlist_menu(menu)
     elseif keyword == 'profiles' then
-        update_profiles_menu(item)
+        update_profiles_menu(menu)
     end
 end
 
@@ -409,12 +425,13 @@ local function dyn_menu_check(items)
 end
 
 -- menu data update callback
-local function update_menu(name, items)
+local function menu_data_cb(name, items)
     if not items or #items == 0 then return end
-    mp.unobserve_property(update_menu)
+    mp.unobserve_property(menu_data_cb)
 
     menu_items = items
     dyn_menu_check(menu_items)
+    mp.commandv('script-message', 'menu-ready')
 end
 
 -- commit menu items if changed
@@ -425,6 +442,45 @@ local function update_menu_items()
     end
 end
 
+-- script message: get <keyword> <src>
+mp.register_script_message('get', function(keyword, src)
+    if not src or src == '' then
+        msg.warn('get: ignored message with empty src')
+        return
+    end
+
+    local menu = dyn_menus[keyword]
+    local reply = { keyword = keyword }
+    if menu then reply.item = menu.item else reply.error = 'keyword not found' end
+    mp.commandv('script-message-to', src, 'menu-get-reply', utils.format_json(reply))
+end)
+
+-- script message: update <keyword> <json>
+mp.register_script_message('update', function(keyword, json)
+    local menu = dyn_menus[keyword]
+    if not menu then return end
+    local item = menu.item
+
+    local data, err = utils.parse_json(json)
+    if not data and err then
+        msg.error('update: failed to parse json: ' .. err)
+        return
+    end
+    if not data.title or data.title == '' then data.title = item.title end
+    if not data.type or data.type == '' then data.type = item.type end
+
+    -- remove old property observers to avoid conflicts
+    if #menu.fns > 0 then
+        for _, fn in ipairs(menu.fns) do mp.unobserve_property(fn) end
+        menu.fns = {}
+    end
+
+    for k, _ in pairs(item) do item[k] = nil end
+    for k, v in pairs(data) do item[k] = v end
+
+    menu_items_dirty = false
+end)
+
 -- update menu items when idle, this reduces the update frequency
 mp.register_idle(update_menu_items)
 
@@ -435,6 +491,7 @@ mp.register_idle(update_menu_items)
 --       scripts that also update the menu data property.
 if #menu_items > 0 then
     dyn_menu_check(menu_items)
+    mp.commandv('script-message', 'menu-ready')
 else
-    mp.observe_property(menu_prop, 'native', update_menu)
+    mp.observe_property(menu_prop, 'native', menu_data_cb)
 end