diff --git a/src/components/widget/TOC.astro b/src/components/widget/TOC.astro
index eb55578..126809d 100644
--- a/src/components/widget/TOC.astro
+++ b/src/components/widget/TOC.astro
@@ -256,6 +256,7 @@ class TableOfContents extends HTMLElement {
     };
 }
 
-customElements.define("table-of-contents", TableOfContents);
-
+if (!customElements.get("table-of-contents")) {
+    customElements.define("table-of-contents", TableOfContents);
+}
 </script>
\ No newline at end of file