diff --git a/js/toc.js b/js/toc.js
diff --git a/js/vendors~html2canvas.js b/js/vendors~html2canvas.js
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mdx",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",

diff --git a/src/toc.js b/src/toc.js
@@ -153,13 +153,17 @@ function addToc(titleList) {
 
 const debouncedReflow = debounce(() => {
     const tabEle = ele('#mdx-toc-select');
-    const halfWidth = tabEle.clientWidth / 2;
-    const borderEle = tabEle.getElementsByClassName('mdui-tab-indicator')[0];
+    if (tabEle) {
+        const halfWidth = tabEle.clientWidth / 2;
+        const borderEle = tabEle.getElementsByClassName('mdui-tab-indicator')[0];
 
-    if (borderEle.style.left !== '0px') {
-        borderEle.style.left = `${halfWidth}px`;
+        if (borderEle) {
+            if (borderEle.style.left !== '0px') {
+                borderEle.style.left = `${halfWidth}px`;
+            }
+            borderEle.style.width = `${halfWidth}px`;
+        }
     }
-    borderEle.style.width = `${halfWidth}px`;
 }, 300);
 
 window.addEventListener('resize', function () {

diff --git a/style.css b/style.css
diff --git a/webpack.config.js b/webpack.config.js
@@ -2,7 +2,7 @@ const path = require('path');
 const webpack = require('webpack');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
 
-const mdxVersion = '2.0.3';
+const mdxVersion = '2.0.4';
 
 module.exports = {
     entry: {
@@ -22,7 +22,7 @@ module.exports = {
     optimization: {
         splitChunks: {
             cacheGroups: {
-                common: { 
+                common: {
                     name: 'common',
                     chunks (chunk) {
                         return chunk.name !== 'login';