diff --git a/js/dark_theme.js b/js/dark_theme.js
new file mode 100644
index 00000000..b540fb11
--- /dev/null
+++ b/js/dark_theme.js
@@ -0,0 +1,9 @@
+function toggleDarkMode() {
+  document.body.classList.toggle("dark");
+  var currentCSS = document.getElementById("highlight-css");
+  if (currentCSS.getAttribute("href") === "file/css/highlightjs/github-dark.min.css") {
+    currentCSS.setAttribute("href", "file/css/highlightjs/github.min.css");
+  } else {
+    currentCSS.setAttribute("href", "file/css/highlightjs/github-dark.min.css");
+  }
+}