diff --git a/src/content/index.js b/src/content/index.js
index 93d2171..95c76ed 100644
--- a/src/content/index.js
+++ b/src/content/index.js
@@ -86,7 +86,7 @@ const getSelectedText = () => {
   const isInTextField = element.tagName === "INPUT" || element.tagName === "TEXTAREA";
   const selectedText = isInTextField
     ? element.value.substring(element.selectionStart, element.selectionEnd)
-    : window.getSelection().toString();
+    : window.getSelection()?.toString() ?? "";
   return selectedText;
 };