diff --git a/server/ui-src/components/message/MessageItem.vue b/server/ui-src/components/message/MessageItem.vue
index c14f294..7085600 100644
--- a/server/ui-src/components/message/MessageItem.vue
+++ b/server/ui-src/components/message/MessageItem.vue
@@ -216,7 +216,7 @@ export default {
 
 		resizeIframe(el) {
 			const i = el.target;
-			if (typeof i.contentWindow.document.body.scrollHeight === "number") {
+			if (i.contentWindow?.document?.body) {
 				i.style.height = i.contentWindow.document.body.scrollHeight + 50 + "px";
 			}
 		},
@@ -226,10 +226,8 @@ export default {
 				return;
 			}
 			const h = document.getElementById("preview-html");
-			if (h) {
-				if (typeof h.contentWindow.document.body.scrollHeight === "number") {
-					h.style.height = h.contentWindow.document.body.scrollHeight + 50 + "px";
-				}
+			if (h?.contentWindow?.document?.body) {
+				h.style.height = h.contentWindow.document.body.scrollHeight + 50 + "px";
 			}
 		},