diff --git a/src/js/static-net-filtering.js b/src/js/static-net-filtering.js
index b67213ff1..3bc743248 100644
--- a/src/js/static-net-filtering.js
+++ b/src/js/static-net-filtering.js
@@ -26,6 +26,7 @@
 /******************************************************************************/
 
 import globals from './globals.js';
+import { queueTask, dropTask } from './tasks.js';
 import HNTrieContainer from './hntrie.js';
 import { sparseBase64 } from './base64-custom.js';
 import { BidiTrieContainer } from './biditrie.js';
@@ -3544,7 +3545,7 @@ const FilterContainer = function() {
     this.selfieVersion = '1';
 
     this.MAX_TOKEN_LENGTH = MAX_TOKEN_LENGTH;
-    this.optimizeTimerId = undefined;
+    this.optimizeTaskId = undefined;
     // As long as CategoryCount is reasonably low, we will use an array to
     // store buckets using category bits as index. If ever CategoryCount
     // becomes too large, we can just go back to using a Map.
@@ -3590,9 +3591,9 @@ FilterContainer.prototype.reset = function() {
     filterSequenceWritePtr = FILTER_SEQUENCES_MIN;
 
     // Cancel potentially pending optimization run.
-    if ( this.optimizeTimerId !== undefined ) {
-        globals.cancelIdleCallback(this.optimizeTimerId);
-        this.optimizeTimerId = undefined;
+    if ( this.optimizeTaskId !== undefined ) {
+        dropTask(this.optimizeTaskId);
+        this.optimizeTaskId = undefined;
     }
 
     // Runtime registers
@@ -3690,20 +3691,20 @@ FilterContainer.prototype.freeze = function() {
     // Optimizing is not critical for the static network filtering engine to
     // work properly, so defer this until later to allow for reduced delay to
     // readiness when no valid selfie is available.
-    if ( this.optimizeTimerId === undefined ) {
-        this.optimizeTimerId = globals.requestIdleCallback(( ) => {
-            this.optimizeTimerId = undefined;
+    if ( this.optimizeTaskId === undefined ) {
+        this.optimizeTaskId = queueTask(( ) => {
+            this.optimizeTaskId = undefined;
             this.optimize();
-        }, { timeout: 5000 });
+        });
     }
 };
 
 /******************************************************************************/
 
 FilterContainer.prototype.optimize = function() {
-    if ( this.optimizeTimerId !== undefined ) {
-        globals.cancelIdleCallback(this.optimizeTimerId);
-        this.optimizeTimerId = undefined;
+    if ( this.optimizeTaskId !== undefined ) {
+        dropTask(this.optimizeTaskId);
+        this.optimizeTaskId = undefined;
     }
 
     for ( let bits = 0, n = this.categories.length; bits < n; bits++ ) {
diff --git a/src/js/tasks.js b/src/js/tasks.js
new file mode 100644
index 000000000..c06010d43
--- /dev/null
+++ b/src/js/tasks.js
@@ -0,0 +1,42 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2014-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/* globals requestIdleCallback, cancelIdleCallback */
+
+'use strict';
+
+/******************************************************************************/
+
+export function queueTask(func) {
+    if ( typeof requestIdleCallback === 'undefined' ) {
+        return setTimeout(func, 1);
+    }
+
+    return requestIdleCallback(func, { timeout: 5000 });
+}
+
+export function dropTask(id) {
+    if ( typeof cancelIdleCallback === 'undefined' ) {
+        return clearTimeout(id);
+    }
+
+    return cancelIdleCallback(id);
+}
diff --git a/tools/make-nodejs.sh b/tools/make-nodejs.sh
index ad6a92f8c..874b2b3a4 100755
--- a/tools/make-nodejs.sh
+++ b/tools/make-nodejs.sh
@@ -17,6 +17,7 @@ cp src/js/hntrie.js                  $DES/js
 cp src/js/static-filtering-parser.js $DES/js
 cp src/js/static-net-filtering.js    $DES/js
 cp src/js/static-filtering-io.js     $DES/js
+cp src/js/tasks.js                   $DES/js
 cp src/js/text-utils.js              $DES/js
 cp src/js/uri-utils.js               $DES/js
 cp src/js/url-net-filtering.js       $DES/js