diff --git a/test/integration/test_utils.mjs b/test/integration/test_utils.mjs
index 09a7dcd9d..55f5f82b3 100644
--- a/test/integration/test_utils.mjs
+++ b/test/integration/test_utils.mjs
@@ -543,6 +543,14 @@ async function dragAndDrop(page, selector, translations, steps = 1) {
   await page.waitForSelector("#viewer:not(.noUserSelect)");
 }
 
+function waitForPageChanging(page) {
+  return createPromise(page, resolve => {
+    window.PDFViewerApplication.eventBus.on("pagechanging", resolve, {
+      once: true,
+    });
+  });
+}
+
 function waitForAnnotationEditorLayer(page) {
   return createPromise(page, resolve => {
     window.PDFViewerApplication.eventBus.on(
@@ -944,6 +952,7 @@ export {
   waitForEntryInStorage,
   waitForEvent,
   waitForNoElement,
+  waitForPageChanging,
   waitForPageRendered,
   waitForPointerUp,
   waitForSandboxTrip,
diff --git a/test/integration/viewer_spec.mjs b/test/integration/viewer_spec.mjs
index f2eed67ab..32c446c91 100644
--- a/test/integration/viewer_spec.mjs
+++ b/test/integration/viewer_spec.mjs
@@ -20,6 +20,7 @@ import {
   getSpanRectFromText,
   loadAndWait,
   scrollIntoView,
+  waitForPageChanging,
   waitForPageRendered,
 } from "./test_utils.mjs";
 import { PNG } from "pngjs";
@@ -1273,4 +1274,48 @@ describe("PDF viewer", () => {
       );
     });
   });
+
+  describe("Keyboard scrolling on startup (bug 843653)", () => {
+    let pages;
+
+    beforeEach(async () => {
+      pages = await loadAndWait("tracemonkey.pdf", ".textLayer .endOfContent");
+    });
+
+    afterEach(async () => {
+      await closePages(pages);
+    });
+
+    it("must check that keyboard scrolling works without having to give the focus to the viewer", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          const pdfViewer = await page.evaluateHandle(
+            () => window.PDFViewerApplication.pdfViewer
+          );
+
+          // The viewer should not have the focus.
+          const hasFocus = await pdfViewer.evaluate(viewer =>
+            viewer.container.contains(document.activeElement)
+          );
+          expect(hasFocus).withContext(`In ${browserName}`).toBeFalse();
+
+          let currentPageNumber = await pdfViewer.evaluate(
+            viewer => viewer.currentPageNumber
+          );
+          expect(currentPageNumber).withContext(`In ${browserName}`).toBe(1);
+
+          // Press the 'PageDown' key to check that it works.
+          const handle = await waitForPageChanging(page);
+          await page.keyboard.press("PageDown");
+          await awaitPromise(handle);
+
+          // The second page should be displayed.
+          currentPageNumber = await pdfViewer.evaluate(
+            viewer => viewer.currentPageNumber
+          );
+          expect(currentPageNumber).withContext(`In ${browserName}`).toBe(2);
+        })
+      );
+    });
+  });
 });
diff --git a/web/app.js b/web/app.js
index 084f981d0..8bc23b358 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1455,11 +1455,6 @@ const PDFViewerApplication = {
             spreadMode,
           });
           this.eventBus.dispatch("documentinit", { source: this });
-          // Make all navigation keys work on document load,
-          // unless the viewer is embedded in a web page.
-          if (!this.isViewerEmbedded) {
-            pdfViewer.focus();
-          }
 
           // For documents with different page sizes, once all pages are
           // resolved, ensure that the correct location becomes visible on load.