From 479173ce4507e43d279331df237d1dd834aed070 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 22 Apr 2020 18:04:30 +0200
Subject: [PATCH] Always attempt to dispatch the "webviewerloaded" event at the
 embedding `document` (PR 10318 follow-up, issue 11829)

This is necessary in order to support cases where the default viewer is embedded in a *dynamically* created <iframe> element.

In order to also support a use-case where there's *multiple* <iframe> elements (containing default viewers) on the same page, the "webviewerloaded" event now includes a `source` detail parameter such that it's possible to associate an event with the relevant DOM element.
---
 web/viewer.js | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/web/viewer.js b/web/viewer.js
index 6b6cccd4a..a59f08ec7 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -211,8 +211,20 @@ function webViewerLoad() {
       // set various `AppOptions`, by dispatching an event once all viewer
       // files are loaded but *before* the viewer initialization has run.
       const event = document.createEvent("CustomEvent");
-      event.initCustomEvent("webviewerloaded", true, true, {});
-      document.dispatchEvent(event);
+      event.initCustomEvent("webviewerloaded", true, true, {
+        source: window,
+      });
+      try {
+        // Attempt to dispatch the event at the embedding `document`,
+        // in order to support cases where the viewer is embedded in
+        // a *dynamically* created <iframe> element.
+        parent.document.dispatchEvent(event);
+      } catch (ex) {
+        // The viewer could be in e.g. a cross-origin <iframe> element,
+        // fallback to dispatching the event at the current `document`.
+        console.error(`webviewerloaded: ${ex}`);
+        document.dispatchEvent(event);
+      }
     }
 
     pdfjsWebApp.PDFViewerApplication.run(config);