diff --git a/public/assets/js/toc.js b/public/assets/js/toc.js
new file mode 100644
index 0000000..24ddbb2
--- /dev/null
+++ b/public/assets/js/toc.js
@@ -0,0 +1,23 @@
+(function () {
+    var headings = document.querySelectorAll('.post-content h2, .post-content h3');
+    var links    = document.querySelectorAll('.toc-list a');
+    if (!headings.length || !links.length) return;
+
+    var map = {};
+    links.forEach(function (a) {
+        map[decodeURIComponent(a.getAttribute('href').slice(1))] = a;
+    });
+
+    var active = null;
+    var observer = new IntersectionObserver(function (entries) {
+        entries.forEach(function (entry) {
+            if (entry.isIntersecting) {
+                if (active) active.classList.remove('toc-active');
+                active = map[entry.target.id] || null;
+                if (active) active.classList.add('toc-active');
+            }
+        });
+    }, { rootMargin: '-8% 0px -82% 0px', threshold: 0 });
+
+    headings.forEach(function (h) { observer.observe(h); });
+})();
diff --git a/templates/post_view.php b/templates/post_view.php
index 8bdcc7f..0aefb68 100644
--- a/templates/post_view.php
+++ b/templates/post_view.php
@@ -308,31 +308,7 @@ $hasSources     = (!empty($externalLinks) || !empty($files))
 </div><!-- /row -->
 
 <?php if (count($_tocItems) >= 3): ?>
-<script>
-(function () {
-    var headings = document.querySelectorAll('.post-content h2, .post-content h3');
-    var links    = document.querySelectorAll('.toc-list a');
-    if (!headings.length || !links.length) return;
-
-    var map = {};
-    links.forEach(function (a) {
-        map[decodeURIComponent(a.getAttribute('href').slice(1))] = a;
-    });
-
-    var active = null;
-    var observer = new IntersectionObserver(function (entries) {
-        entries.forEach(function (entry) {
-            if (entry.isIntersecting) {
-                if (active) active.classList.remove('toc-active');
-                active = map[entry.target.id] || null;
-                if (active) active.classList.add('toc-active');
-            }
-        });
-    }, { rootMargin: '-8% 0px -82% 0px', threshold: 0 });
-
-    headings.forEach(function (h) { observer.observe(h); });
-})();
-</script>
+<script src="/assets/js/toc.js" defer></script>
 <?php endif; ?>
 
 <?php