diff --git a/platform/mv3/scriptlets/abort-on-property-read.js b/platform/mv3/scriptlets/abort-on-property-read.js
index 4896fe508..f9197515e 100644
--- a/platform/mv3/scriptlets/abort-on-property-read.js
+++ b/platform/mv3/scriptlets/abort-on-property-read.js
@@ -100,7 +100,7 @@ const scriptlet = (
     makeProxy(owner, chain);
     const oe = window.onerror;
     window.onerror = function(msg, src, line, col, error) {
-        if ( typeof msg === 'string' && msg.indexOf(magic) !== -1 ) {
+        if ( typeof msg === 'string' && msg.includes(magic) ) {
             return true;
         }
         if ( oe instanceof Function ) {
diff --git a/platform/mv3/scriptlets/abort-on-property-write.js b/platform/mv3/scriptlets/abort-on-property-write.js
new file mode 100644
index 000000000..8cbe8deb3
--- /dev/null
+++ b/platform/mv3/scriptlets/abort-on-property-write.js
@@ -0,0 +1,119 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2019-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
+
+    The scriptlets below are meant to be injected only into a
+    web page context.
+*/
+
+/* jshint esversion:11 */
+
+'use strict';
+
+/******************************************************************************/
+
+/// name abort-on-property-write
+/// alias aopw
+
+/******************************************************************************/
+
+// Important!
+// Isolate from global scope
+(function() {
+
+/******************************************************************************/
+
+// $rulesetId$
+
+const argsMap = new Map(self.$argsMap$);
+
+const hostnamesMap = new Map(self.$hostnamesMap$);
+
+/******************************************************************************/
+
+const magic =
+    String.fromCharCode(Date.now() % 26 + 97) +
+    Math.floor(Math.random() * 982451653 + 982451653).toString(36);
+
+const abort = function() {
+    throw new ReferenceError(magic);
+};
+
+const scriptlet = (
+    prop = ''
+) => {
+    let owner = window;
+    for (;;) {
+        const pos = prop.indexOf('.');
+        if ( pos === -1 ) { break; }
+        owner = owner[prop.slice(0, pos)];
+        if ( owner instanceof Object === false ) { return; }
+        prop = prop.slice(pos + 1);
+    }
+    delete owner[prop];
+    Object.defineProperty(owner, prop, {
+        set: function() {
+            abort();
+        }
+    });
+    const oe = window.onerror;
+    window.onerror = function(msg, src, line, col, error) {
+        if ( typeof msg === 'string' && msg.includes(magic) ) {
+            return true;
+        }
+        if ( oe instanceof Function ) {
+            return oe(msg, src, line, col, error);
+        }
+    }.bind();
+};
+
+/******************************************************************************/
+
+let hn;
+try { hn = document.location.hostname; } catch(ex) { }
+while ( hn ) {
+    if ( hostnamesMap.has(hn) ) {
+        let argsHashes = hostnamesMap.get(hn);
+        if ( typeof argsHashes === 'number' ) { argsHashes = [ argsHashes ]; }
+        for ( const argsHash of argsHashes ) {
+            const details = argsMap.get(argsHash);
+            if ( details.n && details.n.includes(hn) ) { continue; }
+            try { scriptlet(...details.a); } catch(ex) {}
+        }
+    }
+    if ( hn === '*' ) { break; }
+    const pos = hn.indexOf('.');
+    if ( pos !== -1 ) {
+        hn = hn.slice(pos + 1);
+    } else {
+        hn = '*';
+    }
+}
+
+/******************************************************************************/
+
+argsMap.clear();
+hostnamesMap.clear();
+
+/******************************************************************************/
+
+})();
+
+/******************************************************************************/
+
diff --git a/platform/mv3/scriptlets/no-settimeout-if.js b/platform/mv3/scriptlets/no-settimeout-if.js
new file mode 100644
index 000000000..c0331abc6
--- /dev/null
+++ b/platform/mv3/scriptlets/no-settimeout-if.js
@@ -0,0 +1,123 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2019-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
+
+    The scriptlets below are meant to be injected only into a
+    web page context.
+*/
+
+/* jshint esversion:11 */
+
+'use strict';
+
+/******************************************************************************/
+
+/// name no-setTimeout-if
+/// alias nostif
+
+/******************************************************************************/
+
+// Important!
+// Isolate from global scope
+(function() {
+
+/******************************************************************************/
+
+// $rulesetId$
+
+const argsMap = new Map(self.$argsMap$);
+
+const hostnamesMap = new Map(self.$hostnamesMap$);
+
+/******************************************************************************/
+
+const scriptlet = (
+    needle = '',
+    delay = '',
+    
+) => {
+    const needleNot = needle.charAt(0) === '!';
+    if ( needleNot ) { needle = needle.slice(1); }
+    if ( delay === '' ) { delay = undefined; }
+    let delayNot = false;
+    if ( delay !== undefined ) {
+        delayNot = delay.charAt(0) === '!';
+        if ( delayNot ) { delay = delay.slice(1); }
+        delay = parseInt(delay, 10);
+    }
+    if ( needle.startsWith('/') && needle.endsWith('/') ) {
+        needle = needle.slice(1,-1);
+    } else if ( needle !== '' ) {
+        needle = needle.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+    }
+    const reNeedle = new RegExp(needle);
+    const regexpTest = RegExp.prototype.test.call;
+    self.setTimeout = new Proxy(self.setTimeout, {
+        apply: function(target, thisArg, args) {
+            const a = String(args[0]);
+            const b = args[1];
+            let defuse;
+            if ( needle !== '' ) {
+                defuse = regexpTest(reNeedle, a) !== needleNot;
+            }
+            if ( defuse !== false && delay !== undefined ) {
+                defuse = (b === delay || isNaN(b) && isNaN(delay) ) !== delayNot;
+            }
+            if ( defuse ) {
+                args[0] = function(){};
+            }
+            return target.apply(thisArg, args);
+        }
+    });
+};
+
+/******************************************************************************/
+
+let hn;
+try { hn = document.location.hostname; } catch(ex) { }
+while ( hn ) {
+    if ( hostnamesMap.has(hn) ) {
+        let argsHashes = hostnamesMap.get(hn);
+        if ( typeof argsHashes === 'number' ) { argsHashes = [ argsHashes ]; }
+        for ( const argsHash of argsHashes ) {
+            const details = argsMap.get(argsHash);
+            if ( details.n && details.n.includes(hn) ) { continue; }
+            try { scriptlet(...details.a); } catch(ex) {}
+        }
+    }
+    if ( hn === '*' ) { break; }
+    const pos = hn.indexOf('.');
+    if ( pos !== -1 ) {
+        hn = hn.slice(pos + 1);
+    } else {
+        hn = '*';
+    }
+}
+
+/******************************************************************************/
+
+argsMap.clear();
+hostnamesMap.clear();
+
+/******************************************************************************/
+
+})();
+
+/******************************************************************************/
+