diff --git a/web/app.js b/web/app.js
index e483d1797..9987f9bfe 100644
--- a/web/app.js
+++ b/web/app.js
@@ -657,26 +657,22 @@ const PDFViewerApplication = {
   },
 
   get supportsFullscreen() {
-    let support;
     if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
-      support =
-        document.fullscreenEnabled === true ||
-        document.mozFullScreenEnabled === true;
-    } else {
-      const doc = document.documentElement;
-      support = !!(
-        doc.requestFullscreen ||
-        doc.mozRequestFullScreen ||
-        doc.webkitRequestFullScreen
-      );
+      return shadow(this, "supportsFullscreen", document.fullscreenEnabled);
+    }
+    const doc = document.documentElement;
+    let support = !!(
+      doc.requestFullscreen ||
+      doc.mozRequestFullScreen ||
+      doc.webkitRequestFullScreen
+    );
 
-      if (
-        document.fullscreenEnabled === false ||
-        document.mozFullScreenEnabled === false ||
-        document.webkitFullscreenEnabled === false
-      ) {
-        support = false;
-      }
+    if (
+      document.fullscreenEnabled === false ||
+      document.mozFullScreenEnabled === false ||
+      document.webkitFullscreenEnabled === false
+    ) {
+      support = false;
     }
     return shadow(this, "supportsFullscreen", support);
   },
diff --git a/web/pdf_presentation_mode.js b/web/pdf_presentation_mode.js
index f9ad45280..cf0c119de 100644
--- a/web/pdf_presentation_mode.js
+++ b/web/pdf_presentation_mode.js
@@ -86,14 +86,22 @@ class PDFPresentationMode {
     this._setSwitchInProgress();
     this._notifyStateChange();
 
-    if (this.container.requestFullscreen) {
-      this.container.requestFullscreen();
-    } else if (this.container.mozRequestFullScreen) {
-      this.container.mozRequestFullScreen();
-    } else if (this.container.webkitRequestFullscreen) {
-      this.container.webkitRequestFullscreen(Element.ALLOW_KEYBOARD_INPUT);
+    if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
+      if (this.container.requestFullscreen) {
+        this.container.requestFullscreen();
+      } else {
+        return false;
+      }
     } else {
-      return false;
+      if (this.container.requestFullscreen) {
+        this.container.requestFullscreen();
+      } else if (this.container.mozRequestFullScreen) {
+        this.container.mozRequestFullScreen();
+      } else if (this.container.webkitRequestFullscreen) {
+        this.container.webkitRequestFullscreen(Element.ALLOW_KEYBOARD_INPUT);
+      } else {
+        return false;
+      }
     }
 
     this.args = {
@@ -148,6 +156,9 @@ class PDFPresentationMode {
   }
 
   get isFullscreen() {
+    if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
+      return !!document.fullscreenElement;
+    }
     return !!(
       document.fullscreenElement ||
       document.mozFullScreen ||
@@ -468,8 +479,8 @@ class PDFPresentationMode {
     this.fullscreenChangeBind = this._fullscreenChange.bind(this);
 
     window.addEventListener("fullscreenchange", this.fullscreenChangeBind);
-    window.addEventListener("mozfullscreenchange", this.fullscreenChangeBind);
     if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
+      window.addEventListener("mozfullscreenchange", this.fullscreenChangeBind);
       window.addEventListener(
         "webkitfullscreenchange",
         this.fullscreenChangeBind
@@ -482,11 +493,11 @@ class PDFPresentationMode {
    */
   _removeFullscreenChangeListeners() {
     window.removeEventListener("fullscreenchange", this.fullscreenChangeBind);
-    window.removeEventListener(
-      "mozfullscreenchange",
-      this.fullscreenChangeBind
-    );
     if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
+      window.removeEventListener(
+        "mozfullscreenchange",
+        this.fullscreenChangeBind
+      );
       window.removeEventListener(
         "webkitfullscreenchange",
         this.fullscreenChangeBind