diff --git a/index.html b/index.html
index beff238..506aeb2 100644
--- a/index.html
+++ b/index.html
@@ -11,6 +11,33 @@
   </head>
   <body>
     <div style="background-color: rgb(247, 247, 247)">
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
       <figni-viewer
         id="view"
         item-id="9zsj5h47"
@@ -64,6 +91,33 @@
           冷凍庫
         </button>
       </figni-viewer>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
+      <p>a</p>
     </div>
     <script>
       const view = document.getElementById('view')
diff --git a/package.json b/package.json
index e463d70..a4783a4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@cynack/figni-viewer",
-  "version": "0.0.14",
+  "version": "0.0.15",
   "description": "",
   "main": "./dist/figni-viewer.min.js",
   "files": [
diff --git a/src/index.js b/src/index.js
index 0a1214f..67e69c7 100644
--- a/src/index.js
+++ b/src/index.js
@@ -2,6 +2,8 @@ import { ModelViewerElement } from '@google/model-viewer'
 import axios from 'axios'
 
 const API_BASE = 'https://api.stg.figni.store/api'
+const SOCKET_BASE = 'wss://api.stg.figni.store/ws'
+const VIEW_THRESHOLD = 0.7
 
 class FigniViewerElement extends ModelViewerElement {
   static #MODEL_ATTRIBUTE = ['item-id', 'token', 'model-tag']
@@ -24,9 +26,41 @@ class FigniViewerElement extends ModelViewerElement {
   #panels = []
   #hotspots = []
 
+  #initTime = 0
+  #appearedTime = 0
+  #sumViewTime = 0
+  #wasInViewport = false
+  #ws
+
   constructor() {
     super()
 
+    window.onload = () => {
+      this.#ws = new WebSocket(SOCKET_BASE)
+      this.#initTime = performance.now()
+      this.#wasInViewport = this.#isInViewport
+      if (this.#isInViewport) {
+        this.#appearedTime = performance.now()
+      }
+      setInterval(() => {
+        this.#ws.send(
+          JSON.stringify({
+            client_token: this.token,
+            client_version: VERSION,
+            stay_time: this.#stayTime,
+            view_time: this.#viewTime,
+          })
+        )
+      }, 1000)
+    }
+    window.onscroll = () => {
+      if (!this.#wasInViewport && this.#isInViewport) {
+        this.#appearedTime = performance.now()
+      } else if (this.#wasInViewport && !this.#isInViewport) {
+        this.#sumViewTime += performance.now() - this.#appearedTime
+      }
+      this.#wasInViewport = this.#isInViewport
+    }
     this.#seed = Math.random().toString(36).substring(7)
   }
 
@@ -429,6 +463,49 @@ class FigniViewerElement extends ModelViewerElement {
   #evalEvent(string) {
     Function(string)()
   }
+
+  get #isInViewport() {
+    const rect = this.getBoundingClientRect()
+    const area = rect.width * rect.height
+    const viewArea =
+      (Math.max(
+        Math.min(
+          rect.bottom,
+          window.innerHeight || document.documentElement.clientHeight
+        ),
+        0
+      ) -
+        Math.min(
+          Math.max(rect.top, 0),
+          window.innerHeight || document.documentElement.clientHeight
+        )) *
+      (Math.max(
+        Math.min(
+          rect.right,
+          window.innerWidth || document.documentElement.clientWidth
+        ),
+        0
+      ) -
+        Math.min(
+          Math.max(rect.left, 0),
+          window.innerWidth || document.documentElement.clientWidth
+        ))
+    const ratio = viewArea / area
+    return ratio > VIEW_THRESHOLD
+  }
+
+  get #stayTime() {
+    return Number((performance.now() - this.#initTime).toFixed(2))
+  }
+
+  get #viewTime() {
+    return Number(
+      (
+        this.#sumViewTime +
+        (this.#isInViewport ? performance.now() - this.#appearedTime : 0)
+      ).toFixed(2)
+    )
+  }
 }
 
 customElements.define('figni-viewer', FigniViewerElement)
