diff --git a/book.toml b/book.toml
index 861d5f2..eaeb4f8 100755
--- a/book.toml
+++ b/book.toml
@@ -18,4 +18,5 @@ additional-js = [
     "theme/js/highlight.min.js",
     "theme/js/mathjax.js",
     "theme/js/tocrender.js",
+    "theme/js/page.js",
 ]
diff --git a/theme/index.hbs b/theme/index.hbs
index d61aa55..50c96ab 100755
--- a/theme/index.hbs
+++ b/theme/index.hbs
@@ -84,7 +84,7 @@
             {{/if}}
         </mdui-top-app-bar>
 
-        <mdui-navigation-drawer close-on-overlay-click class="toc-drawer" id="toc-drawer" placement="left" open>
+        <mdui-navigation-drawer close-on-overlay-click class="toc-drawer" id="toc-drawer" placement="left">
         </mdui-navigation-drawer>
         {{/unless}}
 
@@ -201,6 +201,8 @@
 
     <script>hljs.highlightAll();</script>
 
+    <script src="{{ ../path_to_root }}theme/js/page.js"></script>
+
 </body>
 
 </html>
\ No newline at end of file
diff --git a/theme/js/page.js b/theme/js/page.js
new file mode 100644
index 0000000..7597071
--- /dev/null
+++ b/theme/js/page.js
@@ -0,0 +1,3 @@
+if (window.innerWidth > 640) {
+    document.getElementById("toc-drawer").setAttribute('open', true)
+}