diff --git a/src/components/CodemirrorEditor/EditorHeader/PostInfo.vue b/src/components/CodemirrorEditor/EditorHeader/PostInfo.vue
index 860a24bac..f1367220c 100644
--- a/src/components/CodemirrorEditor/EditorHeader/PostInfo.vue
+++ b/src/components/CodemirrorEditor/EditorHeader/PostInfo.vue
@@ -62,7 +62,7 @@ function onUpdate(val: boolean) {
 }
 
 onMounted(() => {
-  extensionInstalled.value = window.$syncer !== `undefined`
+  extensionInstalled.value = window.$syncer !== undefined
 })
 </script>
 
@@ -125,7 +125,7 @@ onMounted(() => {
         <Button variant="outline" @click="dialogVisible = false">
           取 消
         </Button>
-        <Button @click="post">
+        <Button :disabled="!extensionInstalled" @click="post">
           确 定
         </Button>
       </DialogFooter>