diff --git a/examples/nft_improved_worker/main.html b/examples/nft_improved_worker/main.html
index 74a57484..98c5f6ad 100644
--- a/examples/nft_improved_worker/main.html
+++ b/examples/nft_improved_worker/main.html
@@ -21,19 +21,19 @@
 <script src="main.js"></script>
 
 <script>
-    let statsMain = new Stats();
+    var statsMain = new Stats();
     statsMain.showPanel(1); // 0: fps, 1: ms, 2: mb, 3+: custom
     statsMain.domElement.style.position = 'relative';
     statsMain.domElement.style.left = '0px';
     statsMain.domElement.style.top = '0px';
     document.getElementById("stats1").appendChild(statsMain.dom);
 
-    let container = document.getElementById('container');
-    let video = document.getElementById('video');
-    let canvas_draw = document.getElementById('canvas_draw');
+    var container = document.getElementById('container');
+    var video = document.getElementById('video');
+    var canvas_draw = document.getElementById('canvas_draw');
 
     if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
-        let hint = {};
+        var hint = {};
         if (isMobile()) {
             hint = {
                 facingMode: {"ideal": "environment"},
@@ -48,7 +48,7 @@
         navigator.mediaDevices.getUserMedia({video: hint}).then(function (stream) {
             video.srcObject = stream;
             video.play();
-            video.addEventListener("loadedmetadata", () => {
+            video.addEventListener("loadedmetadata", function() {
                 start(container, markers["pinball"], video, video.videoWidth, video.videoHeight, canvas_draw, () => statsMain.update());
             });
         });
diff --git a/examples/nft_improved_worker/main.js b/examples/nft_improved_worker/main.js
index 2240e060..676bf49f 100644
--- a/examples/nft_improved_worker/main.js
+++ b/examples/nft_improved_worker/main.js
@@ -53,10 +53,10 @@ function isMobile() {
     return /Android|mobile|iPad|iPhone/i.test(navigator.userAgent);
 }
 
-let ar = null;
-let markerResult = null;
+var ar = null;
+var markerResult = null;
 
-let markers = {
+var markers = {
     "pinball": {
         width: 1637,
         height: 2048,
@@ -66,18 +66,18 @@ let markers = {
 };
 
 function start(container, marker, video, input_width, input_height, canvas_draw, render_update) {
-    let vw, vh;
-    let sw, sh;
-    let pscale, sscale;
-    let w, h;
-    let pw, ph;
-    let ox, oy;
-
-    let canvas_process = document.createElement('canvas');
-    let context_draw = canvas_draw.getContext('2d');
-    let context_process = canvas_process.getContext('2d');
-
-    let load = () => {
+    var vw, vh;
+    var sw, sh;
+    var pscale, sscale;
+    var w, h;
+    var pw, ph;
+    var ox, oy;
+
+    var canvas_process = document.createElement('canvas');
+    var context_draw = canvas_draw.getContext('2d');
+    var context_process = canvas_process.getContext('2d');
+
+    var load = function() {
         vw = input_width;
         vh = input_height;
 
@@ -105,10 +105,10 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         canvas_process.width = pw;
         canvas_process.height = ph;
 
-        let param = new ARCameraParam('../Data/camera_para-iPhone 5 rear 640x480 1.0m.dat');
+        var param = new ARCameraParam('../Data/camera_para-iPhone 5 rear 640x480 1.0m.dat');
         param.onload = function () {
             ar = new ARController(pw, ph, param);
-            let cameraMatrix = ar.getCameraMatrix();
+            var cameraMatrix = ar.getCameraMatrix();
 
             ar.addEventListener('getNFTMarker', function (ev) {
                 markerResult = {type: "found", matrixGL_RH: JSON.stringify(ev.data.matrixGL_RH), proj: JSON.stringify(cameraMatrix)};
@@ -123,15 +123,15 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         };
     };
 
-    let lasttime = Date.now();
-    let time = 0;
+    var lasttime = Date.now();
+    var time = 0;
 
-    let x = 0;
-    let draw = () => {
+    var x = 0;
+    var draw = function() {
         context_draw.clearRect(0, 0, vw, vh);
         render_update();
-        let now = Date.now();
-        let dt = now - lasttime;
+        var now = Date.now();
+        var dt = now - lasttime;
         time += dt;
         lasttime = now;
 
@@ -142,10 +142,10 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
 
 
         if (!markerResult) return;
-        let proj = JSON.parse(markerResult.proj);
-        let world = JSON.parse(markerResult.matrixGL_RH);
+        var proj = JSON.parse(markerResult.proj);
+        var world = JSON.parse(markerResult.matrixGL_RH);
 
-        let mat = multiplyMatrices(proj, world);
+        var mat = multiplyMatrices(proj, world);
 
         function glpointToCanvas(xyz) {
             return {
@@ -154,22 +154,22 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
             }
         }
         function drawpoint(x, y, z) {
-            let r = transformPoint(mat, {x: x, y: y, z: z});
-            let c = glpointToCanvas(r);
+            var r = transformPoint(mat, {x: x, y: y, z: z});
+            var c = glpointToCanvas(r);
             return c;
         }
 
-        let width = marker.width;
-        let height = marker.height;
-        let dpi = marker.dpi;
+        var width = marker.width;
+        var height = marker.height;
+        var dpi = marker.dpi;
 
-        let w = width / dpi * 2.54 * 10;
-        let h = height / dpi * 2.54 * 10;
+        var w = width / dpi * 2.54 * 10;
+        var h = height / dpi * 2.54 * 10;
 
-        let p1 = drawpoint(0, 0, 0);
-        let p2 = drawpoint(w, 0, 0);
-        let p3 = drawpoint(w, h, 0);
-        let p4 = drawpoint(0, h, 0);
+        var p1 = drawpoint(0, 0, 0);
+        var p2 = drawpoint(w, 0, 0);
+        var p3 = drawpoint(w, h, 0);
+        var p4 = drawpoint(0, h, 0);
         context_draw.beginPath();
         context_draw.moveTo(p1.x, p1.y);
         context_draw.lineTo(p2.x, p2.y);
@@ -186,11 +186,11 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         context_process.drawImage(video, 0, 0, vw, vh, ox, oy, w, h);
         markerResult = null;
         if (ar) {
-            let imageData = context_process.getImageData(0, 0, pw, ph);
+            var imageData = context_process.getImageData(0, 0, pw, ph);
             ar.process(imageData);
         }
     }
-    let tick = () => {
+    var tick = function() {
         process();
         draw();
         requestAnimationFrame(tick);
diff --git a/examples/nft_improved_worker/main_threejs_wasm_worker.html b/examples/nft_improved_worker/main_threejs_wasm_worker.html
index 6e259cb6..f572f3a9 100644
--- a/examples/nft_improved_worker/main_threejs_wasm_worker.html
+++ b/examples/nft_improved_worker/main_threejs_wasm_worker.html
@@ -1,140 +1,140 @@
-<!DOCTYPE html>
-<html>
-<head>
-	<meta charset="utf-8">
-	<title>NFT marker example with Three.js</title>
-	<meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=0.5, maximum-scale=1">
-	<link rel="stylesheet" href="../css/video-style.css">
-</head>
-<body class="loading">
-	<div id="loading" >
-			<img  src="../Data/logo.gif"/>
-			<span class="loading-text">Loading, please wait</span>
-	</div>
-  <!--
-  ==================
-  STATS
-  ==================
-  -->
-
-      <div id="stats" class="ui stats">
-
-          <div id="stats1" class="stats-item">
-              <p class="stats-item-title">
-                  Main
-              </p>
-          </div>
-
-          <div id="stats2" class="stats-item">
-              <p class="stats-item-title">
-                  Worker
-              </p>
-          </div>
-
-      </div>
-
-  <!--
-  ==================
-  CAMERA VIDEO & CANVAS
-  ==================
-  -->
-
-      <div id="app">
-          <video
-              loop
-              autoplay
-              muted
-              playsinline
-              id="video">
-          </video>
-
-          <canvas id="canvas"></canvas>
-      </div>
-
-      <a
-          href="https://raw.githubusercontent.com/artoolkit/artoolkit5/master/doc/Marker%20images/pinball.jpg"
-          class="ui marker"
-          target="_blank">
-          🖼 Marker Image
-      </a>
-
-<script src="../js/third_party/three.js/stats.min.js"></script>
-<script src="../js/third_party/three.js/three.min.js"></script>
-<script src="threejs_wasm_worker.js"></script>
-
-<script>
-
-/**
- * STATS
- */
-let statsMain = new Stats();
-statsMain.showPanel( 0 ); // 0: fps, 1: ms, 2: mb, 3+: custom
-document.getElementById( 'stats1' ).appendChild( statsMain.dom );
-
-let statsWorker = new Stats();
-statsWorker.showPanel( 0 ); // 0: fps, 1: ms, 2: mb, 3+: custom
-document.getElementById( 'stats2' ).appendChild( statsWorker.dom );
-
-/**
- * APP / ELEMENTS
- */
-let container = document.getElementById( 'app' );
-let video = document.getElementById( 'video' );
-let canvas = document.getElementById( 'canvas' );
-
-/**
- * APP / VIDEO STREAM
- */
-
-		if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
-			let hint = {
-					audio: false,
-					video: true
-			};
-			if( window.innerWidth < 800 ) {
-					let width = ( window.innerWidth < window.innerHeight ) ? 240 : 360;
-					let height = ( window.innerWidth < window.innerHeight ) ? 360 : 240;
-
-					let aspectRatio = window.innerWidth / window.innerHeight;
-
-					console.log( width, height );
-
-					hint = {
-							audio: false,
-							video: {
-									facingMode: 'environment',
-									width: { min: width, max: width }
-							},
-					};
-
-					console.log( hint );
-			}
-
-			navigator.mediaDevices.getUserMedia( hint ).then( function( stream ) {
-					video.srcObject = stream;
-					video.addEventListener( 'loadedmetadata', () => {
-							video.play();
-
-							console.log( 'video', video, video.videoWidth, video.videoHeight );
-
-							start(
-									container,
-									markers['pinball'],
-									video,
-									video.videoWidth,
-									video.videoHeight,
-									canvas,
-									function() {
-											statsMain.update()
-									},
-									function() {
-											statsWorker.update();
-									},
-									null
-							);
-					} );
-			} );
-	}
-</script>
-</body>
-</html>
+<!DOCTYPE html>
+<html>
+<head>
+	<meta charset="utf-8">
+	<title>NFT marker example with Three.js</title>
+	<meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=0.5, maximum-scale=1">
+	<link rel="stylesheet" href="../css/video-style.css">
+</head>
+<body class="loading">
+	<div id="loading" >
+			<img  src="../Data/logo.gif"/>
+			<span class="loading-text">Loading, please wait</span>
+	</div>
+  <!--
+  ==================
+  STATS
+  ==================
+  -->
+
+      <div id="stats" class="ui stats">
+
+          <div id="stats1" class="stats-item">
+              <p class="stats-item-title">
+                  Main
+              </p>
+          </div>
+
+          <div id="stats2" class="stats-item">
+              <p class="stats-item-title">
+                  Worker
+              </p>
+          </div>
+
+      </div>
+
+  <!--
+  ==================
+  CAMERA VIDEO & CANVAS
+  ==================
+  -->
+
+      <div id="app">
+          <video
+              loop
+              autoplay
+              muted
+              playsinline
+              id="video">
+          </video>
+
+          <canvas id="canvas"></canvas>
+      </div>
+
+      <a
+          href="https://raw.githubusercontent.com/artoolkit/artoolkit5/master/doc/Marker%20images/pinball.jpg"
+          class="ui marker"
+          target="_blank">
+          🖼 Marker Image
+      </a>
+
+<script src="../js/third_party/three.js/stats.min.js"></script>
+<script src="../js/third_party/three.js/three.min.js"></script>
+<script src="threejs_wasm_worker.js"></script>
+
+<script>
+
+/**
+ * STATS
+ */
+var statsMain = new Stats();
+statsMain.showPanel( 0 ); // 0: fps, 1: ms, 2: mb, 3+: custom
+document.getElementById( 'stats1' ).appendChild( statsMain.dom );
+
+var statsWorker = new Stats();
+statsWorker.showPanel( 0 ); // 0: fps, 1: ms, 2: mb, 3+: custom
+document.getElementById( 'stats2' ).appendChild( statsWorker.dom );
+
+/**
+ * APP / ELEMENTS
+ */
+var container = document.getElementById( 'app' );
+var video = document.getElementById( 'video' );
+var canvas = document.getElementById( 'canvas' );
+
+/**
+ * APP / VIDEO STREAM
+ */
+
+		if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
+			var hint = {
+					audio: false,
+					video: true
+			};
+			if( window.innerWidth < 800 ) {
+					var width = ( window.innerWidth < window.innerHeight ) ? 240 : 360;
+					var height = ( window.innerWidth < window.innerHeight ) ? 360 : 240;
+
+					var aspectRatio = window.innerWidth / window.innerHeight;
+
+					console.log( width, height );
+
+					hint = {
+							audio: false,
+							video: {
+									facingMode: 'environment',
+									width: { min: width, max: width }
+							},
+					};
+
+					console.log( hint );
+			}
+
+			navigator.mediaDevices.getUserMedia( hint ).then( function( stream ) {
+					video.srcObject = stream;
+					video.addEventListener( 'loadedmetadata', function() {
+							video.play();
+
+							console.log( 'video', video, video.videoWidth, video.videoHeight );
+
+							start(
+									container,
+									markers['pinball'],
+									video,
+									video.videoWidth,
+									video.videoHeight,
+									canvas,
+									function() {
+											statsMain.update()
+									},
+									function() {
+											statsWorker.update();
+									},
+									null
+							);
+					} );
+			} );
+	}
+</script>
+</body>
+</html>
diff --git a/examples/nft_improved_worker/main_threejs_worker.html b/examples/nft_improved_worker/main_threejs_worker.html
index b0e5d719..588bbabb 100644
--- a/examples/nft_improved_worker/main_threejs_worker.html
+++ b/examples/nft_improved_worker/main_threejs_worker.html
@@ -36,27 +36,27 @@
     <script src="threejs_worker.js"></script>
 
     <script>
-        let statsMain = new Stats();
+        var statsMain = new Stats();
         statsMain.showPanel(1); // 0: fps, 1: ms, 2: mb, 3+: custom
         statsMain.domElement.style.position = 'relative';
         statsMain.domElement.style.left = '0px';
         statsMain.domElement.style.top = '0px';
         document.getElementById("stats1").appendChild(statsMain.dom);
 
-        let statsWorker = new Stats();
+        var statsWorker = new Stats();
         statsWorker.showPanel(1); // 0: fps, 1: ms, 2: mb, 3+: custom
         statsWorker.domElement.style.position = 'relative';
         statsWorker.domElement.style.left = '0px';
         statsWorker.domElement.style.top = '0px';
         document.getElementById("stats2").appendChild(statsWorker.dom);
 
-        let container = document.getElementById('container');
-        let greyCover = document.querySelector('.grey-cover');
-        let video = document.getElementById('video');
-        let canvas_draw = document.getElementById('canvas_draw');
+        var container = document.getElementById('container');
+        var greyCover = document.querySelector('.grey-cover');
+        var video = document.getElementById('video');
+        var canvas_draw = document.getElementById('canvas_draw');
 
         if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
-            let hint = {};
+            var hint = {};
             if (isMobile()) {
                 hint = {
                     facingMode: { "ideal": "environment" },
@@ -70,7 +70,7 @@
 
             navigator.mediaDevices.getUserMedia({ video: hint }).then(function (stream) {
                 video.srcObject = stream;
-                video.addEventListener("loadedmetadata", () => {
+                video.addEventListener("loadedmetadata", function() {
                     video.play();
                     start(container, markers["pinball"], video, video.videoWidth, video.videoHeight, canvas_draw, () => statsMain.update(), () => statsWorker.update(), greyCover);
                 });
diff --git a/examples/nft_improved_worker/main_worker.html b/examples/nft_improved_worker/main_worker.html
index d19bf712..60558e7a 100644
--- a/examples/nft_improved_worker/main_worker.html
+++ b/examples/nft_improved_worker/main_worker.html
@@ -21,26 +21,26 @@
 <script src="main_worker.js"></script>
 
 <script>
-    let statsMain = new Stats();
+    var statsMain = new Stats();
     statsMain.showPanel(1); // 0: fps, 1: ms, 2: mb, 3+: custom
     statsMain.domElement.style.position = 'relative';
     statsMain.domElement.style.left = '0px';
     statsMain.domElement.style.top = '0px';
     document.getElementById("stats1").appendChild(statsMain.dom);
 
-    let statsWorker = new Stats();
+    var statsWorker = new Stats();
     statsWorker.showPanel(1); // 0: fps, 1: ms, 2: mb, 3+: custom
     statsWorker.domElement.style.position = 'relative';
     statsWorker.domElement.style.left = '0px';
     statsWorker.domElement.style.top = '0px';
     document.getElementById("stats2").appendChild(statsWorker.dom);
 
-    let container = document.getElementById('container');
-    let video = document.getElementById('video');
-    let canvas_draw = document.getElementById('canvas_draw');
+    var container = document.getElementById('container');
+    var video = document.getElementById('video');
+    var canvas_draw = document.getElementById('canvas_draw');
 
     if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
-        let hint = {};
+        var hint = {};
         if (isMobile()) {
             hint = {
                 facingMode: {"ideal": "environment"},
@@ -55,7 +55,7 @@
         navigator.mediaDevices.getUserMedia({video: hint}).then(function (stream) {
             video.srcObject = stream;
             video.play();
-            video.addEventListener("loadedmetadata", () => {
+            video.addEventListener("loadedmetadata", function() {
                 start(container, markers["pinball"], video, video.videoWidth, video.videoHeight, canvas_draw, () => statsMain.update(), () => statsWorker.update());
             });
         });
diff --git a/examples/nft_improved_worker/main_worker.js b/examples/nft_improved_worker/main_worker.js
index 965e14b5..9489138d 100644
--- a/examples/nft_improved_worker/main_worker.js
+++ b/examples/nft_improved_worker/main_worker.js
@@ -54,7 +54,7 @@ function isMobile() {
     return /Android|mobile|iPad|iPhone/i.test(navigator.userAgent);
 }
 
-let markers = {
+var markers = {
     "pinball": {
         width: 1637,
         height: 2048,
@@ -64,20 +64,20 @@ let markers = {
 };
 
 function start(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update) {
-    let vw, vh;
-    let sw, sh;
-    let pscale, sscale;
-    let w, h;
-    let pw, ph;
-    let ox, oy;
-    let worker;
-    let camera_para = './../examples/Data/camera_para-iPhone 5 rear 640x480 1.0m.dat'
-
-    let canvas_process = document.createElement('canvas');
-    let context_draw = canvas_draw.getContext('2d');
-    let context_process = canvas_process.getContext('2d');
-
-    let load = () => {
+    var vw, vh;
+    var sw, sh;
+    var pscale, sscale;
+    var w, h;
+    var pw, ph;
+    var ox, oy;
+    var worker;
+    var camera_para = './../examples/Data/camera_para-iPhone 5 rear 640x480 1.0m.dat'
+
+    var canvas_process = document.createElement('canvas');
+    var context_draw = canvas_draw.getContext('2d');
+    var context_process = canvas_process.getContext('2d');
+
+    var load = function() {
         vw = input_width;
         vh = input_height;
 
@@ -110,7 +110,7 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         worker.postMessage({type: "load", pw: pw, ph: ph, camera_para: camera_para, marker: '../' + marker.url});
 
         worker.onmessage = (ev) => {
-            let msg = ev.data;
+            var msg = ev.data;
             switch (msg.type) {
                 case "found": {
                     found(msg);
@@ -126,21 +126,21 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         };
     };
 
-    let lastmsg = null;
-    let found = (msg) => {
+    var lastmsg = null;
+    var found = (msg) => {
         lastmsg = msg;
     };
 
-    let lasttime = Date.now();
-    let time = 0;
+    var lasttime = Date.now();
+    var time = 0;
 
-    let x = 0;
+    var x = 0;
 
-    let draw = () => {
+    var draw = function() {
         context_draw.clearRect(0, 0, vw, vh);
         render_update();
-        let now = Date.now();
-        let dt = now - lasttime;
+        var now = Date.now();
+        var dt = now - lasttime;
         time += dt;
         lasttime = now;
 
@@ -150,10 +150,10 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         context_draw.fillRect(x, 0, 5, 10);
 
         if (!lastmsg) return;
-        let proj = JSON.parse(lastmsg.proj);
-        let world = JSON.parse(lastmsg.matrixGL_RH);
+        var proj = JSON.parse(lastmsg.proj);
+        var world = JSON.parse(lastmsg.matrixGL_RH);
 
-        let mat = multiplyMatrices(proj, world);
+        var mat = multiplyMatrices(proj, world);
 
         function glpointToCanvas(xyz) {
             return {
@@ -162,22 +162,22 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
             }
         }
         function drawpoint(x, y, z) {
-            let r = transformPoint(mat, {x: x, y: y, z: z});
-            let c = glpointToCanvas(r);
+            var r = transformPoint(mat, {x: x, y: y, z: z});
+            var c = glpointToCanvas(r);
             return c;
         }
 
-        let width = marker.width;
-        let height = marker.height;
-        let dpi = marker.dpi;
+        var width = marker.width;
+        var height = marker.height;
+        var dpi = marker.dpi;
 
-        let w = width / dpi * 2.54 * 10;
-        let h = height / dpi * 2.54 * 10;
+        var w = width / dpi * 2.54 * 10;
+        var h = height / dpi * 2.54 * 10;
 
-        let p1 = drawpoint(0, 0, 0);
-        let p2 = drawpoint(w, 0, 0);
-        let p3 = drawpoint(w, h, 0);
-        let p4 = drawpoint(0, h, 0);
+        var p1 = drawpoint(0, 0, 0);
+        var p2 = drawpoint(w, 0, 0);
+        var p3 = drawpoint(w, h, 0);
+        var p4 = drawpoint(0, h, 0);
         context_draw.beginPath();
         context_draw.moveTo(p1.x, p1.y);
         context_draw.lineTo(p2.x, p2.y);
@@ -193,10 +193,10 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         context_process.fillRect(0, 0, pw, ph);
         context_process.drawImage(video, 0, 0, vw, vh, ox, oy, w, h);
 
-        let imageData = context_process.getImageData(0, 0, pw, ph);
+        var imageData = context_process.getImageData(0, 0, pw, ph);
         worker.postMessage({type: "process", imagedata: imageData}, [imageData.data.buffer]);
     }
-    let tick = () => {
+    var tick = function() {
         draw();
         requestAnimationFrame(tick);
     };
diff --git a/examples/nft_improved_worker/threejs_wasm_worker.js b/examples/nft_improved_worker/threejs_wasm_worker.js
index 264b6c3d..206ee25c 100644
--- a/examples/nft_improved_worker/threejs_wasm_worker.js
+++ b/examples/nft_improved_worker/threejs_wasm_worker.js
@@ -1,221 +1,224 @@
-function isMobile() {
-    return /Android|mobile|iPad|iPhone/i.test(navigator.userAgent);
-}
-
-const interpolationFactor = 24;
-
-let trackedMatrix = {
-  // for interpolation
-  delta: [
-      0,0,0,0,
-      0,0,0,0,
-      0,0,0,0,
-      0,0,0,0
-  ],
-  interpolated: [
-      0,0,0,0,
-      0,0,0,0,
-      0,0,0,0,
-      0,0,0,0
-  ]
-}
-
-let markers = {
-    "pinball": {
-        width: 1637,
-        height: 2048,
-        dpi: 600,
-        url: "../DataNFT/pinball",
-    },
-};
-
-var setMatrix = function (matrix, value) {
-    let array = [];
-    for (let key in value) {
-        array[key] = value[key];
-    }
-    if (typeof matrix.elements.set === "function") {
-        matrix.elements.set(array);
-    } else {
-        matrix.elements = [].slice.call(array);
-    }
-};
-
-let worker;
-function start(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update) {
-    worker = new Worker('wasm_worker/artoolkit.wasm_worker.js');
-    worker.onmessage = (ev) => {
-        start2(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update);
-    }
-}
-function start2(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update) {
-    let vw, vh;
-    let sw, sh;
-    let pscale, sscale;
-    let w, h;
-    let pw, ph;
-    let ox, oy;
-    let camera_para = './../../Data/camera_para-iPhone 5 rear 640x480 1.0m.dat'
-
-    let canvas_process = document.createElement('canvas');
-    let context_process = canvas_process.getContext('2d');
-
-    // let context_draw = canvas_draw.getContext('2d');
-    let renderer = new THREE.WebGLRenderer({canvas: canvas_draw, alpha: true, antialias: true});
-    renderer.setPixelRatio(window.devicePixelRatio);
-
-    let scene = new THREE.Scene();
-
-    let camera = new THREE.Camera();
-    camera.matrixAutoUpdate = false;
-    // let camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
-    // camera.position.z = 400;
-
-    scene.add(camera);
-
-    let sphere = new THREE.Mesh(
-        new THREE.SphereGeometry(0.5, 8, 8),
-        new THREE.MeshNormalMaterial()
-    );
-
-    let root = new THREE.Object3D();
-    scene.add(root);
-
-    sphere.material.shading = THREE.FlatShading;
-    sphere.position.z = 0;
-    sphere.position.x = 40;
-    sphere.position.y = 40;
-    sphere.scale.set(80, 80, 80);
-
-    root.matrixAutoUpdate = false;
-    root.add(sphere);
-
-    let load = () => {
-        vw = input_width;
-        vh = input_height;
-
-        pscale = 320 / Math.max(vw, vh / 3 * 4);
-        sscale = isMobile() ? window.outerWidth / input_width : 1;
-
-        sw = vw * sscale;
-        sh = vh * sscale;
-        video.style.width = sw + "px";
-        video.style.height = sh + "px";
-        container.style.width = sw + "px";
-        container.style.height = sh + "px";
-        canvas_draw.style.clientWidth = sw + "px";
-        canvas_draw.style.clientHeight = sh + "px";
-        canvas_draw.width = sw;
-        canvas_draw.height = sh;
-        w = vw * pscale;
-        h = vh * pscale;
-        pw = Math.max(w, h / 3 * 4);
-        ph = Math.max(h, w / 4 * 3);
-        ox = (pw - w) / 2;
-        oy = (ph - h) / 2;
-        canvas_process.style.clientWidth = pw + "px";
-        canvas_process.style.clientHeight = ph + "px";
-        canvas_process.width = pw;
-        canvas_process.height = ph;
-
-        renderer.setSize(sw, sh);
-
-        worker.postMessage({type: "load", pw: pw, ph: ph, camera_para: camera_para, marker: '../' + marker.url});
-
-        worker.onmessage = (ev) => {
-            let msg = ev.data;
-            switch (msg.type) {
-                case "loaded": {
-                    let proj = JSON.parse(msg.proj);
-                    let ratioW = pw / w;
-                    let ratioH = ph / h;
-                    proj[0] *= ratioW;
-                    proj[4] *= ratioW;
-                    proj[8] *= ratioW;
-                    proj[12] *= ratioW;
-                    proj[1] *= ratioH;
-                    proj[5] *= ratioH;
-                    proj[9] *= ratioH;
-                    proj[13] *= ratioH;
-                    setMatrix(camera.projectionMatrix, proj);
-                    break;
-                }
-                case "endLoading": {
-                  if (msg.end == true)
-                    // removing loader page if present
-                    document.body.classList.remove("loading");
-                  document.getElementById("loading").remove();
-                  break;
-                }
-                case "found": {
-                    found(msg);
-                    break;
-                }
-                case "not found": {
-                    found(null);
-                    break;
-                }
-            }
-            track_update();
-            process();
-        };
-    };
-
-    let world;
-
-    let found = msg => {
-      if (!msg) {
-        world = null;
-      } else {
-        world = JSON.parse(msg.matrixGL_RH);
-      }
-    };
-
-    let lasttime = Date.now();
-    let time = 0;
-
-    let draw = () => {
-        render_update();
-        let now = Date.now();
-        let dt = now - lasttime;
-        time += dt;
-        lasttime = now;
-
-        if (!world) {
-            sphere.visible = false;
-        } else {
-            sphere.visible = true;
-
-                  // interpolate matrix
-                  for (let i = 0; i < 16; i++) {
-                    trackedMatrix.delta[i] = world[i] - trackedMatrix.interpolated[i];
-                    trackedMatrix.interpolated[i] =
-                      trackedMatrix.interpolated[i] +
-                      trackedMatrix.delta[i] / interpolationFactor;
-                  }
-
-                  // set matrix of 'root' by detected 'world' matrix
-                  setMatrix(root.matrix, trackedMatrix.interpolated);
-        }
-        renderer.render(scene, camera);
-    };
-
-    function process() {
-      context_process.fillStyle = "black";
-      context_process.fillRect(0, 0, pw, ph);
-      context_process.drawImage(video, 0, 0, vw, vh, ox, oy, w, h);
-
-      let imageData = context_process.getImageData(0, 0, pw, ph);
-      worker.postMessage({ type: "process", imagedata: imageData }, [
-        imageData.data.buffer
-      ]);
-    }
-    let tick = () => {
-        draw();
-        requestAnimationFrame(tick);
-    };
-
-    load();
-    tick();
-    process();
-}
+function isMobile() {
+    return /Android|mobile|iPad|iPhone/i.test(navigator.userAgent);
+}
+
+var interpolationFactor = 24;
+
+var trackedMatrix = {
+  // for interpolation
+  delta: [
+      0,0,0,0,
+      0,0,0,0,
+      0,0,0,0,
+      0,0,0,0
+  ],
+  interpolated: [
+      0,0,0,0,
+      0,0,0,0,
+      0,0,0,0,
+      0,0,0,0
+  ]
+}
+
+var markers = {
+    "pinball": {
+        width: 1637,
+        height: 2048,
+        dpi: 600,
+        url: "../DataNFT/pinball",
+    },
+};
+
+var setMatrix = function (matrix, value) {
+    var array = [];
+    for (var key in value) {
+        array[key] = value[key];
+    }
+    if (typeof matrix.elements.set === "function") {
+        matrix.elements.set(array);
+    } else {
+        matrix.elements = [].slice.call(array);
+    }
+};
+
+var worker;
+function start(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update) {
+    worker = new Worker('wasm_worker/artoolkit.wasm_worker.js');
+    worker.onmessage = function(ev) {
+        start2(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update);
+    }
+}
+
+function start2(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update) {
+    var vw, vh;
+    var sw, sh;
+    var pscale, sscale;
+    var w, h;
+    var pw, ph;
+    var ox, oy;
+    var camera_para = './../../Data/camera_para-iPhone 5 rear 640x480 1.0m.dat'
+
+    var canvas_process = document.createElement('canvas');
+    var context_process = canvas_process.getContext('2d');
+
+    // var context_draw = canvas_draw.getContext('2d');
+    var renderer = new THREE.WebGLRenderer({canvas: canvas_draw, alpha: true, antialias: true});
+    renderer.setPixelRatio(window.devicePixelRatio);
+
+    var scene = new THREE.Scene();
+
+    var camera = new THREE.Camera();
+    camera.matrixAutoUpdate = false;
+    // var camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
+    // camera.position.z = 400;
+
+    scene.add(camera);
+
+    var sphere = new THREE.Mesh(
+        new THREE.SphereGeometry(0.5, 8, 8),
+        new THREE.MeshNormalMaterial()
+    );
+
+    var root = new THREE.Object3D();
+    scene.add(root);
+
+    sphere.material.shading = THREE.FlatShading;
+    sphere.position.z = 0;
+    sphere.position.x = 40;
+    sphere.position.y = 40;
+    sphere.scale.set(80, 80, 80);
+
+    root.matrixAutoUpdate = false;
+    root.add(sphere);
+
+    var load = () => {
+        vw = input_width;
+        vh = input_height;
+
+        pscale = 320 / Math.max(vw, vh / 3 * 4);
+        sscale = isMobile() ? window.outerWidth / input_width : 1;
+
+        sw = vw * sscale;
+        sh = vh * sscale;
+        video.style.width = sw + "px";
+        video.style.height = sh + "px";
+        container.style.width = sw + "px";
+        container.style.height = sh + "px";
+        canvas_draw.style.clientWidth = sw + "px";
+        canvas_draw.style.clientHeight = sh + "px";
+        canvas_draw.width = sw;
+        canvas_draw.height = sh;
+        w = vw * pscale;
+        h = vh * pscale;
+        pw = Math.max(w, h / 3 * 4);
+        ph = Math.max(h, w / 4 * 3);
+        ox = (pw - w) / 2;
+        oy = (ph - h) / 2;
+        canvas_process.style.clientWidth = pw + "px";
+        canvas_process.style.clientHeight = ph + "px";
+        canvas_process.width = pw;
+        canvas_process.height = ph;
+
+        renderer.setSize(sw, sh);
+
+        worker.postMessage({type: "load", pw: pw, ph: ph, camera_para: camera_para, marker: '../' + marker.url});
+
+        worker.onmessage = function(ev) {
+            var msg = ev.data;
+            switch (msg.type) {
+                case "loaded": {
+                    var proj = JSON.parse(msg.proj);
+                    var ratioW = pw / w;
+                    var ratioH = ph / h;
+                    proj[0] *= ratioW;
+                    proj[4] *= ratioW;
+                    proj[8] *= ratioW;
+                    proj[12] *= ratioW;
+                    proj[1] *= ratioH;
+                    proj[5] *= ratioH;
+                    proj[9] *= ratioH;
+                    proj[13] *= ratioH;
+                    setMatrix(camera.projectionMatrix, proj);
+                    break;
+                }
+
+                case "endLoading": {
+                  if (msg.end == true)
+                    // removing loader page if present
+                    document.body.classList.remove("loading");
+                  document.getElementById("loading").remove();
+                  break;
+                }
+
+                case "found": {
+                    found(msg);
+                    break;
+                }
+
+                case "not found": {
+                    found(null);
+                    break;
+                }
+            }
+
+            track_update();
+            process();
+        };
+    };
+
+    var world;
+
+    var found = function(msg) {
+      if (!msg) {
+        world = null;
+      } else {
+        world = JSON.parse(msg.matrixGL_RH);
+      }
+    };
+
+    var lasttime = Date.now();
+
+    var draw = function() {
+        render_update();
+        var now = Date.now();
+        var dt = now - lasttime;
+        time += dt;
+        lasttime = now;
+
+        if (!world) {
+            sphere.visible = false;
+        } else {
+            sphere.visible = true;
+                  // interpolate matrix
+                  for (var i = 0; i < 16; i++) {
+                    trackedMatrix.delta[i] = world[i] - trackedMatrix.interpolated[i];
+                    trackedMatrix.interpolated[i] =
+                      trackedMatrix.interpolated[i] +
+                      trackedMatrix.delta[i] / interpolationFactor;
+                  }
+
+                  // set matrix of 'root' by detected 'world' matrix
+                  setMatrix(root.matrix, trackedMatrix.interpolated);
+        }
+        renderer.render(scene, camera);
+    };
+
+    function process() {
+      context_process.fillStyle = "black";
+      context_process.fillRect(0, 0, pw, ph);
+      context_process.drawImage(video, 0, 0, vw, vh, ox, oy, w, h);
+
+      var imageData = context_process.getImageData(0, 0, pw, ph);
+      worker.postMessage({ type: "process", imagedata: imageData }, [
+        imageData.data.buffer
+      ]);
+    }
+    var tick = function() {
+        draw();
+        requestAnimationFrame(tick);
+    };
+
+    load();
+    tick();
+    process();
+}
diff --git a/examples/nft_improved_worker/threejs_worker.js b/examples/nft_improved_worker/threejs_worker.js
index 32c75e69..b6642438 100644
--- a/examples/nft_improved_worker/threejs_worker.js
+++ b/examples/nft_improved_worker/threejs_worker.js
@@ -2,7 +2,7 @@ function isMobile() {
     return /Android|mobile|iPad|iPhone/i.test(navigator.userAgent);
 }
 
-let markers = {
+var markers = {
     "pinball": {
         width: 1637,
         height: 2048,
@@ -12,8 +12,8 @@ let markers = {
 };
 
 var setMatrix = function (matrix, value) {
-    let array = [];
-    for (let key in value) {
+    var array = [];
+    for (var key in value) {
         array[key] = value[key];
     }
     if (typeof matrix.elements.set === "function") {
@@ -24,37 +24,37 @@ var setMatrix = function (matrix, value) {
 };
 
 function start(container, marker, video, input_width, input_height, canvas_draw, render_update, track_update, greyCover) {
-    let vw, vh;
-    let sw, sh;
-    let pscale, sscale;
-    let w, h;
-    let pw, ph;
-    let ox, oy;
-    let worker;
-    let camera_para = './../examples/Data/camera_para-iPhone 5 rear 640x480 1.0m.dat'
-
-    let canvas_process = document.createElement('canvas');
-    let context_process = canvas_process.getContext('2d');
-
-    // let context_draw = canvas_draw.getContext('2d');
-    let renderer = new THREE.WebGLRenderer({ canvas: canvas_draw, alpha: true, antialias: true });
+    var vw, vh;
+    var sw, sh;
+    var pscale, sscale;
+    var w, h;
+    var pw, ph;
+    var ox, oy;
+    var worker;
+    var camera_para = './../examples/Data/camera_para-iPhone 5 rear 640x480 1.0m.dat'
+
+    var canvas_process = document.createElement('canvas');
+    var context_process = canvas_process.getContext('2d');
+
+    // var context_draw = canvas_draw.getContext('2d');
+    var renderer = new THREE.WebGLRenderer({ canvas: canvas_draw, alpha: true, antialias: true });
     renderer.setPixelRatio(window.devicePixelRatio);
 
-    let scene = new THREE.Scene();
+    var scene = new THREE.Scene();
 
-    let camera = new THREE.Camera();
+    var camera = new THREE.Camera();
     camera.matrixAutoUpdate = false;
-    // let camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
+    // var camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
     // camera.position.z = 400;
 
     scene.add(camera);
 
-    let sphere = new THREE.Mesh(
+    var sphere = new THREE.Mesh(
         new THREE.SphereGeometry(0.5, 8, 8),
         new THREE.MeshNormalMaterial()
     );
 
-    let root = new THREE.Object3D();
+    var root = new THREE.Object3D();
     scene.add(root);
 
     sphere.material.shading = THREE.FlatShading;
@@ -66,7 +66,7 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
     root.matrixAutoUpdate = false;
     root.add(sphere);
 
-    let load = () => {
+    var load = function() {
         vw = input_width;
         vh = input_height;
 
@@ -100,13 +100,13 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
 
         worker.postMessage({ type: "load", pw: pw, ph: ph, camera_para: camera_para, marker: '../' + marker.url });
 
-        worker.onmessage = (ev) => {
-            let msg = ev.data;
+        worker.onmessage = function(ev) {
+            var msg = ev.data;
             switch (msg.type) {
                 case "loaded": {
-                    let proj = JSON.parse(msg.proj);
-                    let ratioW = pw / w;
-                    let ratioH = ph / h;
+                    var proj = JSON.parse(msg.proj);
+                    var ratioW = pw / w;
+                    var ratioH = ph / h;
                     proj[0] *= ratioW;
                     proj[4] *= ratioW;
                     proj[8] *= ratioW;
@@ -137,33 +137,33 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         };
     };
 
-    let lastmsg = null;
-    let found = (msg) => {
+    var lastmsg = null;
+    var found = function(msg) {
         lastmsg = msg;
     };
 
-    let lasttime = Date.now();
-    let time = 0;
+    var lasttime = Date.now();
+    var time = 0;
 
-    let draw = () => {
+    var draw = function() {
         render_update();
-        let now = Date.now();
-        let dt = now - lasttime;
+        var now = Date.now();
+        var dt = now - lasttime;
         time += dt;
         lasttime = now;
 
         if (!lastmsg) {
             sphere.visible = false;
         } else {
-            let proj = JSON.parse(lastmsg.proj);
-            let world = JSON.parse(lastmsg.matrixGL_RH);
+            var proj = JSON.parse(lastmsg.proj);
+            var world = JSON.parse(lastmsg.matrixGL_RH);
 
-            let width = marker.width;
-            let height = marker.height;
-            let dpi = marker.dpi;
+            var width = marker.width;
+            var height = marker.height;
+            var dpi = marker.dpi;
 
-            let w = width / dpi * 2.54 * 10;
-            let h = height / dpi * 2.54 * 10;
+            var w = width / dpi * 2.54 * 10;
+            var h = height / dpi * 2.54 * 10;
 
             sphere.visible = true;
             setMatrix(root.matrix, world);
@@ -176,10 +176,10 @@ function start(container, marker, video, input_width, input_height, canvas_draw,
         context_process.fillRect(0, 0, pw, ph);
         context_process.drawImage(video, 0, 0, vw, vh, ox, oy, w, h);
 
-        let imageData = context_process.getImageData(0, 0, pw, ph);
+        var imageData = context_process.getImageData(0, 0, pw, ph);
         worker.postMessage({ type: "process", imagedata: imageData }, [imageData.data.buffer]);
     }
-    let tick = () => {
+    var tick = function() {
         draw();
         requestAnimationFrame(tick);
     };
diff --git a/examples/nft_improved_worker/threejs_worker_gltf.html b/examples/nft_improved_worker/threejs_worker_gltf.html
index 527cad83..67ec4abc 100644
--- a/examples/nft_improved_worker/threejs_worker_gltf.html
+++ b/examples/nft_improved_worker/threejs_worker_gltf.html
@@ -59,23 +59,23 @@
       /**
        * STATS
        */
-      let statsMain = new Stats();
+      var statsMain = new Stats();
       statsMain.showPanel(0); // 0: fps, 1: ms, 2: mb, 3+: custom
       document.getElementById("stats1").appendChild(statsMain.dom);
 
-      let statsWorker = new Stats();
+      var statsWorker = new Stats();
       statsWorker.showPanel(0); // 0: fps, 1: ms, 2: mb, 3+: custom
       document.getElementById("stats2").appendChild(statsWorker.dom);
 
       /**
        * APP / ELEMENTS
        */
-      let container = document.getElementById("app");
-      let video = document.getElementById("video");
-      let canvas = document.getElementById("canvas");
+      var container = document.getElementById("app");
+      var video = document.getElementById("video");
+      var canvas = document.getElementById("canvas");
 
       if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
-        let hint = {
+        var hint = {
           audio: false,
           video: true
         };
@@ -96,7 +96,7 @@
 
         navigator.mediaDevices.getUserMedia(hint).then(function(stream) {
           video.srcObject = stream;
-          video.addEventListener("loadedmetadata", () => {
+          video.addEventListener("loadedmetadata", function() {
             video.play();
 
             start(
diff --git a/examples/nft_improved_worker/threejs_worker_gltf.js b/examples/nft_improved_worker/threejs_worker_gltf.js
index 528257c2..a6669e67 100644
--- a/examples/nft_improved_worker/threejs_worker_gltf.js
+++ b/examples/nft_improved_worker/threejs_worker_gltf.js
@@ -1,14 +1,14 @@
-let model;
-const clock = new THREE.Clock();
-let mixers = [];
+var model;
+var clock = new THREE.Clock();
+var mixers = [];
 
 function isMobile() {
     return /Android|mobile|iPad|iPhone/i.test(navigator.userAgent);
 }
 
-const interpolationFactor = 24;
+var interpolationFactor = 24;
 
-let trackedMatrix = {
+var trackedMatrix = {
     // for interpolation
     delta: [
         0, 0, 0, 0,
@@ -24,7 +24,7 @@ let trackedMatrix = {
     ]
 }
 
-let markers = {
+var markers = {
     pinball: {
         width: 1637,
         height: 2048,
@@ -34,8 +34,8 @@ let markers = {
 };
 
 var setMatrix = function (matrix, value) {
-    let array = [];
-    for (let key in value) {
+    var array = [];
+    for (var key in value) {
         array[key] = value[key];
     }
     if (typeof matrix.elements.set === "function") {
@@ -46,48 +46,48 @@ var setMatrix = function (matrix, value) {
 };
 
 function start( container, marker, video, input_width, input_height, canvas_draw, render_update, track_update) {
-    let vw, vh;
-    let sw, sh;
-    let pscale, sscale;
-    let w, h;
-    let pw, ph;
-    let ox, oy;
-    let worker;
-    let camera_para = "./../examples/Data/camera_para-iPhone 5 rear 640x480 1.0m.dat";
-
-    let canvas_process = document.createElement("canvas");
-    let context_process = canvas_process.getContext("2d");
-
-    // let context_draw = canvas_draw.getContext('2d');
-    let renderer = new THREE.WebGLRenderer({
+    var vw, vh;
+    var sw, sh;
+    var pscale, sscale;
+    var w, h;
+    var pw, ph;
+    var ox, oy;
+    var worker;
+    var camera_para = "./../examples/Data/camera_para-iPhone 5 rear 640x480 1.0m.dat";
+
+    var canvas_process = document.createElement("canvas");
+    var context_process = canvas_process.getContext("2d");
+
+    // var context_draw = canvas_draw.getContext('2d');
+    var renderer = new THREE.WebGLRenderer({
         canvas: canvas_draw,
         alpha: true,
         antialias: true
     });
     renderer.setPixelRatio(window.devicePixelRatio);
 
-    let scene = new THREE.Scene();
+    var scene = new THREE.Scene();
 
-    let camera = new THREE.Camera();
+    var camera = new THREE.Camera();
     camera.matrixAutoUpdate = false;
-    // let camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
+    // var camera = new THREE.PerspectiveCamera(70, window.innerWidth / window.innerHeight, 1, 1000);
     // camera.position.z = 400;
 
     scene.add(camera);
 
-    const light = new THREE.AmbientLight(0xffffff);
+    var light = new THREE.AmbientLight(0xffffff);
     scene.add(light);
 
-    let sphere = new THREE.Mesh(
+    var sphere = new THREE.Mesh(
         new THREE.SphereGeometry(0.5, 8, 8),
         new THREE.MeshNormalMaterial()
     );
 
-    let root = new THREE.Object3D();
+    var root = new THREE.Object3D();
     scene.add(root);
 
     /* Load Model */
-    let threeGLTFLoader = new THREE.GLTFLoader();
+    var threeGLTFLoader = new THREE.GLTFLoader();
 
     threeGLTFLoader.load("../Data/models/Flamingo.glb", function (gltf) {
             model = gltf.scene.children[0];
@@ -95,10 +95,10 @@ function start( container, marker, video, input_width, input_height, canvas_draw
             model.position.x = 100;
             model.position.y = 100;
 
-            const animation = gltf.animations[0];
-            const mixer = new THREE.AnimationMixer(model);
+            var animation = gltf.animations[0];
+            var mixer = new THREE.AnimationMixer(model);
             mixers.push(mixer);
-            const action = mixer.clipAction(animation);
+            var action = mixer.clipAction(animation);
             action.play();
 
             root.matrixAutoUpdate = false;
@@ -106,7 +106,7 @@ function start( container, marker, video, input_width, input_height, canvas_draw
         }
     );
 
-    let load = () => {
+    var load = function() {
         vw = input_width;
         vh = input_height;
 
@@ -146,13 +146,13 @@ function start( container, marker, video, input_width, input_height, canvas_draw
             marker: marker.url
         });
 
-        worker.onmessage = ev => {
-            let msg = ev.data;
+        worker.onmessage = function(ev) {
+            var msg = ev.data;
             switch (msg.type) {
                 case "loaded": {
-                    let proj = JSON.parse(msg.proj);
-                    let ratioW = pw / w;
-                    let ratioH = ph / h;
+                    var proj = JSON.parse(msg.proj);
+                    var ratioW = pw / w;
+                    var ratioH = ph / h;
                     proj[0] *= ratioW;
                     proj[4] *= ratioW;
                     proj[8] *= ratioW;
@@ -168,7 +168,7 @@ function start( container, marker, video, input_width, input_height, canvas_draw
                 case "endLoading": {
                     if (msg.end == true) {
                         // removing loader page if present
-                        let loader = document.getElementById('loading');
+                        var loader = document.getElementById('loading');
                         if (loader) {
                             loader.querySelector('.loading-text').innerText = 'Start the tracking!';
                             setTimeout(function(){
@@ -193,9 +193,9 @@ function start( container, marker, video, input_width, input_height, canvas_draw
         };
     };
 
-    let world;
+    var world;
 
-    let found = msg => {
+    var found = function(msg) {
         if (!msg) {
             world = null;
         } else {
@@ -203,21 +203,21 @@ function start( container, marker, video, input_width, input_height, canvas_draw
         }
     };
 
-    let lasttime = Date.now();
-    let time = 0;
+    var lasttime = Date.now();
+    var time = 0;
 
     function process() {
         context_process.fillStyle = "black";
         context_process.fillRect(0, 0, pw, ph);
         context_process.drawImage(video, 0, 0, vw, vh, ox, oy, w, h);
 
-        let imageData = context_process.getImageData(0, 0, pw, ph);
+        var imageData = context_process.getImageData(0, 0, pw, ph);
         worker.postMessage({ type: "process", imagedata: imageData }, [
             imageData.data.buffer
         ]);
     }
 
-    let tick = () => {
+    var tick = function() {
         draw();
         requestAnimationFrame(tick);
 
@@ -228,10 +228,10 @@ function start( container, marker, video, input_width, input_height, canvas_draw
         }
     };
 
-    let draw = () => {
+    var draw = function() {
         render_update();
-        let now = Date.now();
-        let dt = now - lasttime;
+        var now = Date.now();
+        var dt = now - lasttime;
         time += dt;
         lasttime = now;
 
@@ -241,7 +241,7 @@ function start( container, marker, video, input_width, input_height, canvas_draw
             root.visible = true;
 
             // interpolate matrix
-            for (let i = 0; i < 16; i++) {
+            for (var i = 0; i < 16; i++) {
                 trackedMatrix.delta[i] = world[i] - trackedMatrix.interpolated[i];
                 trackedMatrix.interpolated[i] =
                     trackedMatrix.interpolated[i] +