diff --git a/mediapipe/web/graph_runner/platform_utils.ts b/mediapipe/web/graph_runner/platform_utils.ts
index 7e1decf3..d86e002d 100644
--- a/mediapipe/web/graph_runner/platform_utils.ts
+++ b/mediapipe/web/graph_runner/platform_utils.ts
@@ -32,5 +32,6 @@ export function isIOS() {
     // tslint:disable-next-line:deprecation
   ].includes(navigator.platform)
       // iPad on iOS 13 detection
-      || (navigator.userAgent.includes('Mac') && 'ontouchend' in document);
+      || (navigator.userAgent.includes('Mac') &&
+          (typeof document !== undefined && 'ontouchend' in document));
 }