diff --git a/app/src/protyle/wysiwyg/keydown.ts b/app/src/protyle/wysiwyg/keydown.ts
index 0ed130861..ef209d7dd 100644
--- a/app/src/protyle/wysiwyg/keydown.ts
+++ b/app/src/protyle/wysiwyg/keydown.ts
@@ -93,6 +93,9 @@ export const getContentByInlineHTML = (range: Range, cb: (content: string) => vo
 
 export const keydown = (protyle: IProtyle, editorElement: HTMLElement) => {
     editorElement.addEventListener("keydown", async (event: KeyboardEvent & { target: HTMLElement }) => {
+        if (!event.key) {
+            return;
+        }
         if (event.target.localName === "protyle-html" || event.target.localName === "input") {
             event.stopPropagation();
             return;