From a591a53195ba3a1ebf36c149c72e11800a674a1a Mon Sep 17 00:00:00 2001
From: Yanzhen Yu <yanzhen@smartx.com>
Date: Thu, 18 Feb 2021 11:59:41 +0800
Subject: [PATCH] safe access iframe document

---
 src/snapshot.ts | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/snapshot.ts b/src/snapshot.ts
index 77544656..2c0f67e4 100644
--- a/src/snapshot.ts
+++ b/src/snapshot.ts
@@ -208,7 +208,14 @@ function onceIframeLoaded(
   }
   // document is loading
   let fired = false;
-  if (win.document.readyState !== 'complete') {
+
+  let readyState: DocumentReadyState;
+  try {
+    readyState = win.document.readyState;
+  } catch (error) {
+    return;
+  }
+  if (readyState !== 'complete') {
     const timer = setTimeout(() => {
       if (!fired) {
         listener();