diff --git a/package.json b/package.json
index 842b6bb6e..376ead9d3 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
       "no-unsanitized"
     ],
     "rules": {
-      "no-negated-condition": "warn",
+      "no-negated-condition": "error",
       "no-unsanitized/method": [
         "error",
         {
@@ -76,13 +76,13 @@
           }
         }
       ],
-      "no-unused-vars": "warn",
-      "prefer-destructuring": "warn",
-      "unicorn/no-for-loop": "warn",
-      "unicorn/prefer-includes": "warn",
-      "unicorn/prefer-string-slice": "warn",
+      "no-unused-vars": "error",
+      "prefer-destructuring": "error",
+      "unicorn/no-for-loop": "error",
+      "unicorn/prefer-includes": "error",
+      "unicorn/prefer-string-slice": "error",
       "unicorn/filename-case": "warn",
-      "unicorn/prefer-query-selector": "warn"
+      "unicorn/prefer-query-selector": "error"
     }
   },
   "repository": {
diff --git a/src/main/zapHomeFiles/hud/display.js b/src/main/zapHomeFiles/hud/display.js
index dab7e9e18..22641ea80 100644
--- a/src/main/zapHomeFiles/hud/display.js
+++ b/src/main/zapHomeFiles/hud/display.js
@@ -27,7 +27,7 @@ Vue.component('modal', {
 		close() {
 			this.$emit('close');
 		},
-		afterLeave(element) {
+		afterLeave(_element) {
 			if (!app.keepShowing) {
 				app.backStack = [];
 				hideDisplayFrame();
@@ -402,13 +402,13 @@ Vue.component('http-message-modal', {
 			let header = '';
 			let body = '';
 
-			if (!this.response.isReadonly) {
-				header = this.response.header;
-				body = this.response.body;
-			} else {
+			if (this.response.isReadonly) {
 				method = this.request.method;
 				header = this.request.header;
 				body = this.request.body;
+			} else {
+				header = this.response.header;
+				body = this.response.body;
 			}
 
 			return {method, header, body};
@@ -529,7 +529,7 @@ Vue.component('history-message-modal', {
 			}, [channel.port2]);
 		},
 		ascanRequest() {
-			const request = this.request;
+			const {request} = this;
 			this.$emit('close');
 			navigator.serviceWorker.controller.postMessage(
 				{
@@ -582,7 +582,7 @@ Vue.component('ws-message-modal', {
 	},
 	computed: {
 		currentMessage() {
-			const payload = this.payload;
+			const {payload} = this;
 			return {payload};
 		}
 	}
@@ -736,10 +736,9 @@ Vue.component('site-tree-node', {
 			channel.port1.addEventListener('message', event => {
 				// Remove the ..loading.. child
 				Vue.set(treeNode.model, 'children', []);
-				for (let i = 0; i < event.data.childNodes.length; i++) {
-					const child = event.data.childNodes[i];
+				event.data.childNodes.forEach(child => {
 					treeNode.addChild(child.name, child.method, child.isLeaf, child.hrefId);
-				}
+				});
 			});
 
 			navigator.serviceWorker.controller.postMessage({
@@ -755,7 +754,7 @@ Vue.component('site-tree-node', {
 			if ((name.match(/\//g) || []).length > 2) {
 				// If there are more than 2 slashes just show last url element
 				// The first 2 slashes will be http(s)://...
-				name = name.substring(name.lastIndexOf('/') + 1);
+				name = name.slice(name.lastIndexOf('/') + 1);
 			}
 
 			if (isLeaf) {
@@ -921,8 +920,8 @@ document.addEventListener('DOMContentLoaded', () => {
 });
 
 navigator.serviceWorker.addEventListener('message', event => {
-	const action = event.data.action;
-	const config = event.data.config;
+	const {data: {action}} = event;
+	const {data: {config}} = event;
 	const port = event.ports[0];
 	let show;
 
diff --git a/src/main/zapHomeFiles/hud/drawer.js b/src/main/zapHomeFiles/hud/drawer.js
index 7a6729931..391ec51c6 100644
--- a/src/main/zapHomeFiles/hud/drawer.js
+++ b/src/main/zapHomeFiles/hud/drawer.js
@@ -1,4 +1,5 @@
 // App is the main Vue object controlling everything
+
 let app;
 const eventBus = new Vue();
 let frameId = '';
@@ -55,7 +56,7 @@ Vue.component('history', {
 					return re.test(message.url);
 				}
 
-				return message.url.indexOf(self.filter) >= 0;
+				return message.url.includes(self.filter);
 			});
 		}
 	},
@@ -72,12 +73,12 @@ Vue.component('history', {
 	},
 	watch: {
 		regexEnabled() {
-			this.isRegExError = !this.regexEnabled ? false : this.isRegExError;
+			this.isRegExError = this.regexEnabled ? this.isRegExError : false;
 		},
 		filteredMessages() {
 			this.$nextTick(function () {
 				const visibleMessages = document.querySelectorAll('#history-messages .message-tr');
-				this.hiddenMessageCount = (!this.messages) ? 0 : this.messages.length - visibleMessages.length;
+				this.hiddenMessageCount = this.messages ? this.messages.length - visibleMessages.length : 0;
 				this.historyItemsFiltered();
 			});
 		}
@@ -104,7 +105,7 @@ Vue.component('history', {
 		if (this.messages.length > 0) {
 			const lastMessage = this.messages[this.messages.length - 1];
 			const lastid = 'message-tr-' + lastMessage.id;
-			const lastIdElement = document.getElementById(lastid);
+			const lastIdElement = document.querySelector('#' + lastid);
 
 			if (lastIdElement) {
 				lastIdElement.scrollIntoView({block: 'end', behavior: 'smooth'});
@@ -169,7 +170,7 @@ Vue.component('websockets', {
 					return re.test(message.messageSummary);
 				}
 
-				return message.messageSummary.indexOf(self.filter) >= 0;
+				return message.messageSummary.includes(self.filter);
 			});
 		}
 	},
@@ -186,12 +187,12 @@ Vue.component('websockets', {
 	},
 	watch: {
 		regexEnabled() {
-			this.isRegExError = !this.regexEnabled ? false : this.isRegExError;
+			this.isRegExError = this.regexEnabled ? this.isRegExError : false;
 		},
 		filteredMessages() {
 			this.$nextTick(function () {
 				const visibleMessages = document.querySelectorAll('#websockets-messages .message-tr');
-				this.hiddenMessageCount = (!this.messages) ? 0 : this.messages.length - visibleMessages.length;
+				this.hiddenMessageCount = this.messages ? this.messages.length - visibleMessages.length : 0;
 				this.websocketsItemsFiltered();
 			});
 		}
@@ -315,10 +316,10 @@ Vue.component('tabs', {
 			})
 			.catch(utils.errorHandler);
 
-		eventBus.$on('showTabs', data => {
+		eventBus.$on('showTabs', _data => {
 			this.tabsVisible = true;
 		});
-		eventBus.$on('hideTabs', data => {
+		eventBus.$on('hideTabs', _data => {
 			this.tabsVisible = false;
 			if (this.isOpen) {
 				this.closeDrawer();
@@ -431,7 +432,7 @@ Vue.component('drawer-button-showhide', {
 		showHud() {
 			this.isHudVisible = true;
 			localforage.setItem('settings.isHudVisible', true)
-				.then(function (value) {
+				.then(function (_value) {
 					this.icon = utils.getZapImagePath('radar.png');
 					parent.postMessage({tabId, frameId, action: 'showHudPanels'}, context.url);
 					eventBus.$emit('showTabs', {});
@@ -441,7 +442,7 @@ Vue.component('drawer-button-showhide', {
 		hideHud() {
 			this.isHudVisible = false;
 			localforage.setItem('settings.isHudVisible', false)
-				.then(function (value) {
+				.then(function (_value) {
 					this.icon = utils.getZapImagePath('radar-grey.png');
 					parent.postMessage({tabId, frameId, action: 'hideHudPanels'}, context.url);
 					eventBus.$emit('hideTabs', {});
@@ -477,6 +478,7 @@ document.addEventListener('DOMContentLoaded', () => {
 	tabId = parameters.get('tabId');
 
 	/* Vue app */
+	// eslint-disable-next-line no-unused-vars
 	app = new Vue({
 		i18n: I18n.i18n,
 		el: '#app',
@@ -485,7 +487,7 @@ document.addEventListener('DOMContentLoaded', () => {
 });
 
 navigator.serviceWorker.addEventListener('message', event => {
-	const action = event.data.action;
+	const {data: {action}} = event;
 	const port = event.ports[0];
 
 	switch (action) {
diff --git a/src/main/zapHomeFiles/hud/management.js b/src/main/zapHomeFiles/hud/management.js
index 4bc90ac58..d98e8dd10 100644
--- a/src/main/zapHomeFiles/hud/management.js
+++ b/src/main/zapHomeFiles/hud/management.js
@@ -15,7 +15,6 @@ const ZAP_SHARED_SECRET = '<<ZAP_SHARED_SECRET>>';
 
 let app;
 let tabId = '';
-let frameId = '';
 const urlParameter = utils.getParameter(document.location.href, 'url');
 const context = {
 	url: urlParameter,
@@ -56,7 +55,6 @@ function showTutorial() {
 document.addEventListener('DOMContentLoaded', () => {
 	const parameters = new URL(document.location).searchParams;
 
-	frameId = parameters.get('frameId');
 	tabId = parameters.get('tabId');
 
 	app = new Vue({
diff --git a/src/main/zapHomeFiles/hud/panel.js b/src/main/zapHomeFiles/hud/panel.js
index 32831481d..beee370b2 100644
--- a/src/main/zapHomeFiles/hud/panel.js
+++ b/src/main/zapHomeFiles/hud/panel.js
@@ -212,6 +212,7 @@ document.addEventListener('DOMContentLoaded', () => {
 	window.name = panelKey;
 
 	// Initialize vue app
+	// eslint-disable-next-line no-unused-vars
 	app = new Vue({
 		i18n: I18n.i18n,
 		el: '#app',
diff --git a/src/main/zapHomeFiles/hud/serviceworker.js b/src/main/zapHomeFiles/hud/serviceworker.js
index 89ecd0f99..8962fe2b1 100644
--- a/src/main/zapHomeFiles/hud/serviceworker.js
+++ b/src/main/zapHomeFiles/hud/serviceworker.js
@@ -97,7 +97,7 @@ function initWebSockets() {
 			self.dispatchEvent(ev);
 		} else if ('id' in jevent && 'response' in jevent) {
 			const pFunctions = webSocketCallbacks[jevent.id];
-			const response = jevent.response;
+			const {response} = jevent;
 			if ('code' in response && 'message' in response) {
 				// These always indicate a failure
 				const error = new Error(I18n.t('error_with_message', [response.message]));
@@ -234,6 +234,7 @@ self.addEventListener('error', utils.errorHandler);
 self.addEventListener('hud.log', logHandler);
 self.addEventListener('hud.backup', backupHandler);
 
+// eslint-disable-next-line no-unused-vars
 function registerForZapEvents(publisher) {
 	apiCall('event', 'register', publisher);
 }
diff --git a/src/main/zapHomeFiles/hud/target/inject.js b/src/main/zapHomeFiles/hud/target/inject.js
index 228818c91..dcb2ee3a2 100644
--- a/src/main/zapHomeFiles/hud/target/inject.js
+++ b/src/main/zapHomeFiles/hud/target/inject.js
@@ -33,7 +33,7 @@ const injection = (function () {
 		const r = Math.floor(Math.random() * 1000);
 		const tabId = String(millis) + '-' + r;
 
-		return tabId.substring(6);
+		return tabId.slice(6);
 	}
 
 	/* TARGET INTERACTIONS */
@@ -46,27 +46,27 @@ const injection = (function () {
 	/* Change width of iframe for expanding buttons */
 	function expandPanel(panelOrientation) {
 		// Todo: is this too hacky?
-		const panel = document.getElementById(HUD_PREFIX + panelOrientation + '-panel');
+		const panel = document.querySelector('#' + HUD_PREFIX + panelOrientation + '-panel');
 
 		panel.style.width = '300px';
 	}
 
 	function contractPanel(panelOrientation) {
-		const panel = document.getElementById(HUD_PREFIX + panelOrientation + '-panel');
+		const panel = document.querySelector('#' + HUD_PREFIX + panelOrientation + '-panel');
 
 		panel.style.width = '110px';
 	}
 
 	/* Dynamically size growler iframes with number of alerts */
 	function heightenGrowlerFrame(lines) {
-		const panel = document.getElementById(GROWLER_ALERTS);
+		const panel = document.querySelector('#' + GROWLER_ALERTS);
 		const offset = 56 + (30 * lines);
 
 		panel.style.height = (panel.offsetHeight + offset) + 'px';
 	}
 
 	function shortenGrowlerFrame(lines) {
-		const panel = document.getElementById(GROWLER_ALERTS);
+		const panel = document.querySelector('#' + GROWLER_ALERTS);
 		const offset = 56 + (30 * lines);
 
 		panel.style.height = (panel.offsetHeight - offset) + 'px';
@@ -74,95 +74,95 @@ const injection = (function () {
 
 	/* Dynamically size iframes with number of buttons */
 	function heighten(panelOrientation) {
-		const panel = document.getElementById(HUD_PREFIX + panelOrientation + '-panel');
+		const panel = document.querySelector('#' + HUD_PREFIX + panelOrientation + '-panel');
 
 		panel.style.height = (panel.offsetHeight + 33) + 'px';
 	}
 
 	function shorten(panelOrientation) {
-		const panel = document.getElementById(HUD_PREFIX + panelOrientation + '-panel');
+		const panel = document.querySelector('#' + HUD_PREFIX + panelOrientation + '-panel');
 
 		panel.style.height = (panel.offsetHeight - 33) + 'px';
 	}
 
 	function showHudPanels() {
-		document.getElementById(LEFT_PANEL).style.display = '';
-		document.getElementById(RIGHT_PANEL).style.display = '';
-		const panel = document.getElementById(BOTTOM_DRAWER);
+		document.querySelector('#' + LEFT_PANEL).style.display = '';
+		document.querySelector('#' + RIGHT_PANEL).style.display = '';
+		const panel = document.querySelector('#' + BOTTOM_DRAWER);
 		panel.style.width = '100%';
 		panel.style.left = '0px';
 		panel.style.right = '';
 	}
 
 	function hideHudPanels() {
-		document.getElementById(LEFT_PANEL).style.display = 'none';
-		document.getElementById(RIGHT_PANEL).style.display = 'none';
-		const panel = document.getElementById(BOTTOM_DRAWER);
+		document.querySelector('#' + LEFT_PANEL).style.display = 'none';
+		document.querySelector('#' + RIGHT_PANEL).style.display = 'none';
+		const panel = document.querySelector('#' + BOTTOM_DRAWER);
 		panel.style.width = '90px';
 		panel.style.left = '';
 		panel.style.right = '0px';
 	}
 
 	function hideAllDisplayFrames() {
-		document.getElementById(LEFT_PANEL).style.display = 'none';
-		document.getElementById(RIGHT_PANEL).style.display = 'none';
-		document.getElementById(BOTTOM_DRAWER).style.display = 'none';
-		document.getElementById(GROWLER_ALERTS).style.display = 'none';
+		document.querySelector('#' + LEFT_PANEL).style.display = 'none';
+		document.querySelector('#' + RIGHT_PANEL).style.display = 'none';
+		document.querySelector('#' + BOTTOM_DRAWER).style.display = 'none';
+		document.querySelector('#' + GROWLER_ALERTS).style.display = 'none';
 	}
 
 	function showAllDisplayFrames() {
-		document.getElementById(LEFT_PANEL).style.display = '';
-		document.getElementById(RIGHT_PANEL).style.display = '';
-		document.getElementById(BOTTOM_DRAWER).style.display = '';
-		document.getElementById(GROWLER_ALERTS).style.display = '';
+		document.querySelector('#' + LEFT_PANEL).style.display = '';
+		document.querySelector('#' + RIGHT_PANEL).style.display = '';
+		document.querySelector('#' + BOTTOM_DRAWER).style.display = '';
+		document.querySelector('#' + GROWLER_ALERTS).style.display = '';
 	}
 
 	function refreshAllFrames() {
-		document.getElementById(LEFT_PANEL).src = document.getElementById(LEFT_PANEL).src;
-		document.getElementById(RIGHT_PANEL).src = document.getElementById(RIGHT_PANEL).src;
-		document.getElementById(MAIN_DISPLAY).src = document.getElementById(MAIN_DISPLAY).src;
-		document.getElementById(BOTTOM_DRAWER).src = document.getElementById(BOTTOM_DRAWER).src;
-		document.getElementById(GROWLER_ALERTS).src = document.getElementById(GROWLER_ALERTS).src;
-		document.getElementById(MANAGEMENT).src = document.getElementById(MANAGEMENT).src;
+		document.querySelector('#' + LEFT_PANEL).src = document.querySelector('#' + LEFT_PANEL).src;
+		document.querySelector('#' + RIGHT_PANEL).src = document.querySelector('#' + RIGHT_PANEL).src;
+		document.querySelector('#' + MAIN_DISPLAY).src = document.querySelector('#' + MAIN_DISPLAY).src;
+		document.querySelector('#' + BOTTOM_DRAWER).src = document.querySelector('#' + BOTTOM_DRAWER).src;
+		document.querySelector('#' + GROWLER_ALERTS).src = document.querySelector('#' + GROWLER_ALERTS).src;
+		document.querySelector('#' + MANAGEMENT).src = document.querySelector('#' + MANAGEMENT).src;
 	}
 
 	function refreshDisplayFrames() {
-		document.getElementById(LEFT_PANEL).src = document.getElementById(LEFT_PANEL).src;
-		document.getElementById(RIGHT_PANEL).src = document.getElementById(RIGHT_PANEL).src;
-		document.getElementById(MAIN_DISPLAY).src = document.getElementById(MAIN_DISPLAY).src;
-		document.getElementById(BOTTOM_DRAWER).src = document.getElementById(BOTTOM_DRAWER).src;
-		document.getElementById(GROWLER_ALERTS).src = document.getElementById(GROWLER_ALERTS).src;
+		document.querySelector('#' + LEFT_PANEL).src = document.querySelector('#' + LEFT_PANEL).src;
+		document.querySelector('#' + RIGHT_PANEL).src = document.querySelector('#' + RIGHT_PANEL).src;
+		document.querySelector('#' + MAIN_DISPLAY).src = document.querySelector('#' + MAIN_DISPLAY).src;
+		document.querySelector('#' + BOTTOM_DRAWER).src = document.querySelector('#' + BOTTOM_DRAWER).src;
+		document.querySelector('#' + GROWLER_ALERTS).src = document.querySelector('#' + GROWLER_ALERTS).src;
 	}
 
 	function refreshManagementFrame() {
-		document.getElementById(MANAGEMENT).src = document.getElementById(MANAGEMENT).src;
+		document.querySelector('#' + MANAGEMENT).src = document.querySelector('#' + MANAGEMENT).src;
 	}
 
 	/* Hide or show main iframe for popups and dialogs */
 	function showMainDisplay() {
-		document.getElementById(MAIN_DISPLAY).style.display = '';
+		document.querySelector('#' + MAIN_DISPLAY).style.display = '';
 	}
 
 	function hideMainDisplay() {
-		document.getElementById(MAIN_DISPLAY).style.display = 'none';
+		document.querySelector('#' + MAIN_DISPLAY).style.display = 'none';
 	}
 
 	function showBottomDrawer() {
-		document.getElementById(BOTTOM_DRAWER).style.height = '30%';
+		document.querySelector('#' + BOTTOM_DRAWER).style.height = '30%';
 	}
 
 	function hideBottomDrawer() {
-		document.getElementById(BOTTOM_DRAWER).style.height = '50px';
+		document.querySelector('#' + BOTTOM_DRAWER).style.height = '50px';
 	}
 
 	function expandManagement() {
-		document.getElementById(MANAGEMENT).style.width = '100%';
-		document.getElementById(MANAGEMENT).style.height = '100%';
+		document.querySelector('#' + MANAGEMENT).style.width = '100%';
+		document.querySelector('#' + MANAGEMENT).style.height = '100%';
 	}
 
 	function contractManagement() {
-		document.getElementById(MANAGEMENT).style.width = '0px';
-		document.getElementById(MANAGEMENT).style.height = '0px';
+		document.querySelector('#' + MANAGEMENT).style.width = '0px';
+		document.querySelector('#' + MANAGEMENT).style.height = '0px';
 	}
 
 	// TODO showEnable section - put this code in a separate file and inject ?
@@ -281,13 +281,13 @@ const injection = (function () {
 		}
 
 		// Send to the management frame with the shared secret
-		const iframe = document.getElementById(MANAGEMENT);
+		const iframe = document.querySelector('#' + MANAGEMENT);
 		iframe.contentWindow.postMessage({action: 'showEnable.count', tabId, count, sharedSecret: ZAP_SHARED_SECRET}, ZAP_HUD_FILES);
 	}
 
 	function highlightAlert(alert) {
 		const id = alert.param;
-		let element = document.getElementById(id);
+		let element = document.querySelector('#' + id);
 		if (!element) {
 			const els = document.getElementsByName(id);
 			for (const namedElement of els) {
@@ -416,7 +416,7 @@ const injection = (function () {
 		}
 
 		// Send to the management frame with the shared secret
-		const iframe = document.getElementById(MANAGEMENT);
+		const iframe = document.querySelector('#' + MANAGEMENT);
 		iframe.contentWindow.postMessage({action: 'showComments.count', tabId,
 			count, suspicious: sus, sharedSecret: ZAP_SHARED_SECRET}, ZAP_HUD_FILES);
 	}
@@ -425,7 +425,7 @@ const injection = (function () {
 
 	function showZapAlertInternal(alertId) {
 		// Send to the management frame with the shared secret
-		const iframe = document.getElementById(MANAGEMENT);
+		const iframe = document.querySelector('#' + MANAGEMENT);
 		iframe.contentWindow.postMessage({action: 'commonAlerts.showAlert', alertId, tabId, sharedSecret: ZAP_SHARED_SECRET}, ZAP_HUD_FILES);
 	}
 
@@ -623,8 +623,8 @@ const injection = (function () {
 		if (zapReplaceOffset > 0) {
 			// Hide the zapHudReplaceReq injected when resending a message in the browser
 			// But don't loose any fragment
-			const fragment = window.location.hash.substr(1);
-			let origUrl = window.location.href.substring(0, zapReplaceOffset - 1);
+			const fragment = window.location.hash.slice(1);
+			let origUrl = window.location.href.slice(0, zapReplaceOffset - 1);
 			if (fragment) {
 				origUrl += '#' + fragment;
 			}
diff --git a/src/main/zapHomeFiles/hud/tools/activeScan.js b/src/main/zapHomeFiles/hud/tools/activeScan.js
index 8d92df7bf..45cdb1a03 100644
--- a/src/main/zapHomeFiles/hud/tools/activeScan.js
+++ b/src/main/zapHomeFiles/hud/tools/activeScan.js
@@ -51,17 +51,15 @@ const ActiveScan = (function () {
 				const config = {};
 				config.buttons = [{text: I18n.t('common_cancel'), id: 'cancel'}];
 
-				if (!isRunning) {
-					if (!isInScope) {
-						config.text = DIALOG.START_ADD_SCOPE_1 + domain + DIALOG.START_ADD_SCOPE_2 + domain + DIALOG.START_ADD_SCOPE_3;
-						config.buttons.unshift({text: I18n.t('common_start'), id: 'start-add-to-scope'});
-					} else {
-						config.text = DIALOG.START_1 + domain + DIALOG.START_2;
-						config.buttons.unshift({text: I18n.t('common_start'), id: 'start'});
-					}
-				} else {
+				if (isRunning) {
 					config.text = DIALOG.STOP_1 + tool.runningScope[0] + DIALOG.STOP_2;
 					config.buttons.unshift({text: I18n.t('common_stop'), id: 'stop'});
+				} else if (isInScope) {
+					config.text = DIALOG.START_1 + domain + DIALOG.START_2;
+					config.buttons.unshift({text: I18n.t('common_start'), id: 'start'});
+				} else {
+					config.text = DIALOG.START_ADD_SCOPE_1 + domain + DIALOG.START_ADD_SCOPE_2 + domain + DIALOG.START_ADD_SCOPE_3;
+					config.buttons.unshift({text: I18n.t('common_start'), id: 'start-add-to-scope'});
 				}
 
 				return config;
@@ -150,10 +148,10 @@ const ActiveScan = (function () {
 	function checkIsRunning(tabId) {
 		return new Promise(resolve => {
 			utils.loadTool(NAME).then(tool => {
-				if (tabId !== undefined) {
-					resolve(tool.runningTabId === tabId);
-				} else {
+				if (tabId === undefined) {
 					resolve(tool.isRunning);
+				} else {
+					resolve(tool.runningTabId === tabId);
 				}
 			});
 		});
@@ -207,7 +205,7 @@ const ActiveScan = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		registerForZapEvents(ACTIVE_SCAN_EVENT);
 	});
diff --git a/src/main/zapHomeFiles/hud/tools/ajaxspider.js b/src/main/zapHomeFiles/hud/tools/ajaxspider.js
index 054e543e9..937141635 100644
--- a/src/main/zapHomeFiles/hud/tools/ajaxspider.js
+++ b/src/main/zapHomeFiles/hud/tools/ajaxspider.js
@@ -49,19 +49,19 @@ const AjaxSpider = (function () {
 				config.buttons = [{text: I18n.t('common_cancel'), id: 'cancel'}];
 				config.status = '';
 
-				if (!isRunning) {
+				if (isRunning) {
+					config.status = 'running';
+					config.text = DIALOG.STOP_1 + tool.runningScope[0] + DIALOG.STOP_2;
+					config.buttons.unshift({text: I18n.t('common_stop'), id: 'stop'});
+				} else {
 					config.status = 'stopped';
-					if (!isInScope) {
-						config.text = DIALOG.START_ADD_SCOPE_1 + domain + DIALOG.START_ADD_SCOPE_2 + domain + DIALOG.START_ADD_SCOPE_3;
-						config.buttons.unshift({text: I18n.t('common_start'), id: 'start-add-to-scope'});
-					} else {
+					if (isInScope) {
 						config.text = DIALOG.START_1 + domain + DIALOG.START_2;
 						config.buttons.unshift({text: I18n.t('common_start'), id: 'start'});
+					} else {
+						config.text = DIALOG.START_ADD_SCOPE_1 + domain + DIALOG.START_ADD_SCOPE_2 + domain + DIALOG.START_ADD_SCOPE_3;
+						config.buttons.unshift({text: I18n.t('common_start'), id: 'start-add-to-scope'});
 					}
-				} else {
-					config.status = 'running';
-					config.text = DIALOG.STOP_1 + tool.runningScope[0] + DIALOG.STOP_2;
-					config.buttons.unshift({text: I18n.t('common_stop'), id: 'stop'});
 				}
 
 				return config;
@@ -89,7 +89,7 @@ const AjaxSpider = (function () {
 		utils.getUpgradedUrl(url)
 			.then(upgradedUrl => {
 				apiCallWithResponse('ajaxSpider', 'action', 'setOptionBrowserId', {String: browserId});
-				apiCallWithResponse('ajaxSpider', 'action', 'scan', {url: upgradedUrl}).then(response => {
+				apiCallWithResponse('ajaxSpider', 'action', 'scan', {url: upgradedUrl}).then(_response => {
 					spiderStarted(tabId, upgradedUrl);
 				})
 					.catch(error => {
@@ -114,7 +114,7 @@ const AjaxSpider = (function () {
 	}
 
 	function stopSpider(tabId) {
-		apiCallWithResponse('ajaxSpider', 'action', 'stop').then(response => {
+		apiCallWithResponse('ajaxSpider', 'action', 'stop').then(_response => {
 			spiderStopped(tabId);
 		})
 			.catch(error => {
@@ -122,7 +122,7 @@ const AjaxSpider = (function () {
 			});
 	}
 
-	function spiderStopped(tabId) {
+	function spiderStopped(_tabId) {
 		utils.loadTool(NAME)
 			.then(tool => {
 				tool.isRunning = false;
@@ -177,7 +177,7 @@ const AjaxSpider = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		registerForZapEvents('org.zaproxy.zap.extension.spiderAjax.SpiderEventPublisher');
 	});
diff --git a/src/main/zapHomeFiles/hud/tools/attack.js b/src/main/zapHomeFiles/hud/tools/attack.js
index 35164d3c9..bf317ad11 100644
--- a/src/main/zapHomeFiles/hud/tools/attack.js
+++ b/src/main/zapHomeFiles/hud/tools/attack.js
@@ -38,19 +38,19 @@ const Attack = (function () {
 			.then(isRunning => {
 				const config = {};
 
-				if (!isRunning) {
-					config.text = DIALOG.OFF;
+				if (isRunning) {
+					config.text = DIALOG.ON;
 					config.buttons = [
-						{text: I18n.t('common_turn_on'),
-							id: 'turnon'},
+						{text: I18n.t('common_turn_off'),
+							id: 'turnoff'},
 						{text: I18n.t('common_cancel'),
 							id: 'cancel'}
 					];
 				} else {
-					config.text = DIALOG.ON;
+					config.text = DIALOG.OFF;
 					config.buttons = [
-						{text: I18n.t('common_turn_off'),
-							id: 'turnoff'},
+						{text: I18n.t('common_turn_on'),
+							id: 'turnon'},
 						{text: I18n.t('common_cancel'),
 							id: 'cancel'}
 					];
@@ -76,7 +76,7 @@ const Attack = (function () {
 				utils.zapApiErrorDialog(tabId, error);
 				throw error;
 			})
-			.then(response => {
+			.then(_response => {
 				utils.loadTool(NAME)
 					.then(tool => {
 						tool.isRunning = true;
@@ -98,7 +98,7 @@ const Attack = (function () {
 				utils.zapApiErrorDialog(tabId, error);
 				throw error;
 			})
-			.then(response => {
+			.then(_response => {
 				utils.loadTool(NAME)
 					.then(tool => {
 						tool.isRunning = false;
@@ -155,7 +155,7 @@ const Attack = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/break.js b/src/main/zapHomeFiles/hud/tools/break.js
index 7ac12b134..3f9db1e35 100644
--- a/src/main/zapHomeFiles/hud/tools/break.js
+++ b/src/main/zapHomeFiles/hud/tools/break.js
@@ -47,7 +47,7 @@ const Break = (function () {
 				utils.zapApiErrorDialog(tabId, error);
 				throw error;
 			})
-			.then(response => {
+			.then(_response => {
 				utils.loadTool(NAME)
 					.then(tool => {
 						tool.isRunning = true;
@@ -68,7 +68,7 @@ const Break = (function () {
 				utils.zapApiErrorDialog(tabId, error);
 				throw error;
 			})
-			.then(response => {
+			.then(_response => {
 				utils.loadTool(NAME)
 					.then(tool => {
 						tool.isRunning = false;
@@ -136,15 +136,15 @@ const Break = (function () {
 
 		utils.getAllClients('display')
 			.then(clients => {
-				const isFirefox = this.navigator.userAgent.indexOf('Firefox') > -1;
+				const isFirefox = this.navigator.userAgent.includes('Firefox');
 				let r = false;
 
 				if (isFirefox) {
-					for (let i = 0; i < clients.length; i++) {
-						if (clients[i].visibilityState === 'visible') {
+					clients.forEach(client => {
+						if (client.visibilityState === 'visible') {
 							r = true;
 						}
-					}
+					});
 				} else if (clients.length > 0) {
 					r = true;
 				}
@@ -198,15 +198,15 @@ const Break = (function () {
 	function showBreakWebSocketDisplay(data) {
 		utils.getAllClients('display')
 			.then(clients => {
-				const isFirefox = this.navigator.userAgent.indexOf('Firefox') > -1;
+				const isFirefox = this.navigator.userAgent.includes('Firefox');
 				let r = false;
 
 				if (isFirefox) {
-					for (let i = 0; i < clients.length; i++) {
-						if (clients[i].visibilityState === 'visible') {
+					clients.forEach(client => {
+						if (client.visibilityState === 'visible') {
 							r = true;
 						}
-					}
+					});
 				} else if (clients.length > 0) {
 					r = true;
 				}
@@ -266,7 +266,7 @@ const Break = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		registerForZapEvents('org.zaproxy.zap.extension.brk.BreakEventPublisher');
 	});
diff --git a/src/main/zapHomeFiles/hud/tools/commonAlerts.js b/src/main/zapHomeFiles/hud/tools/commonAlerts.js
index 346442d61..5ecdd593f 100644
--- a/src/main/zapHomeFiles/hud/tools/commonAlerts.js
+++ b/src/main/zapHomeFiles/hud/tools/commonAlerts.js
@@ -31,7 +31,7 @@ const CommonAlerts = (function () {
 		return utils.messageAllTabs('growlerAlerts', {action: 'showGrowlerAlert', alert});
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		registerForZapEvents('org.zaproxy.zap.extension.alert.AlertEventPublisher');
 		registerForZapEvents('org.zaproxy.zap.extension.hud.HudEventPublisher');
@@ -85,7 +85,7 @@ const CommonAlerts = (function () {
 				if (zapReplaceOffset > 0) {
 					// Strip off the string used for resending in the browser
 					// Will be preceded by ? or &
-					origTarget = origTarget.substring(0, zapReplaceOffset - 1);
+					origTarget = origTarget.slice(0, zapReplaceOffset - 1);
 				}
 
 				let target = origTarget;
@@ -145,8 +145,8 @@ const CommonAlerts = (function () {
 								for (const alertName in pageAlerts[alertRisk]) {
 									if (Object.prototype.hasOwnProperty.call(pageAlerts[alertRisk], alertName)) {
 										const reportedParameters = new Set();
-										for (let i = 0; i < pageAlerts[alertRisk][alertName].length; i++) {
-											const alert = pageAlerts[alertRisk][alertName][i];
+
+										pageAlerts[alertRisk][alertName].forEach(alert => {
 											if (alert.param.length > 0 && !reportedParameters.has(alert.param)) {
 												reportedParameters.add(alert.param);
 												utils.messageFrame(event.detail.tabId, 'management', {
@@ -156,7 +156,7 @@ const CommonAlerts = (function () {
 													risk: alert.risk,
 													param: alert.param});
 											}
-										}
+										});
 									}
 								}
 							}
@@ -196,7 +196,7 @@ const CommonAlerts = (function () {
 			}
 
 			const risk = event.detail.riskString;
-			const name = event.detail.name;
+			const {detail: {name}} = event;
 
 			if (alertCache[targetDomain][risk][name] === undefined) {
 				alertCache[targetDomain][risk][name] = {};
diff --git a/src/main/zapHomeFiles/hud/tools/history.js b/src/main/zapHomeFiles/hud/tools/history.js
index 37737839c..9d8817e8b 100644
--- a/src/main/zapHomeFiles/hud/tools/history.js
+++ b/src/main/zapHomeFiles/hud/tools/history.js
@@ -142,7 +142,7 @@ const History = (function () {
 		utils.writeTool(tool);
 	});
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		registerForZapEvents('org.parosproxy.paros.extension.history.ProxyListenerLogEventPublisher');
 	});
diff --git a/src/main/zapHomeFiles/hud/tools/htmlReport.js b/src/main/zapHomeFiles/hud/tools/htmlReport.js
index 8f9da8a71..c26a91bb2 100644
--- a/src/main/zapHomeFiles/hud/tools/htmlReport.js
+++ b/src/main/zapHomeFiles/hud/tools/htmlReport.js
@@ -43,7 +43,7 @@ const HtmlReport = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/hudErrors.js b/src/main/zapHomeFiles/hud/tools/hudErrors.js
index b84468f20..fa864c06e 100644
--- a/src/main/zapHomeFiles/hud/tools/hudErrors.js
+++ b/src/main/zapHomeFiles/hud/tools/hudErrors.js
@@ -82,7 +82,7 @@ const HudErrors = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/pageAlertsHigh.js b/src/main/zapHomeFiles/hud/tools/pageAlertsHigh.js
index 2f152d0ad..bfa70bb64 100644
--- a/src/main/zapHomeFiles/hud/tools/pageAlertsHigh.js
+++ b/src/main/zapHomeFiles/hud/tools/pageAlertsHigh.js
@@ -42,7 +42,7 @@ const PageAlertsHigh = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/pageAlertsInformational.js b/src/main/zapHomeFiles/hud/tools/pageAlertsInformational.js
index d4d5cb805..f608ae7e6 100644
--- a/src/main/zapHomeFiles/hud/tools/pageAlertsInformational.js
+++ b/src/main/zapHomeFiles/hud/tools/pageAlertsInformational.js
@@ -43,7 +43,7 @@ const PageAlertsInformational = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/pageAlertsLow.js b/src/main/zapHomeFiles/hud/tools/pageAlertsLow.js
index 1b2133009..a959ff5bb 100644
--- a/src/main/zapHomeFiles/hud/tools/pageAlertsLow.js
+++ b/src/main/zapHomeFiles/hud/tools/pageAlertsLow.js
@@ -42,7 +42,7 @@ const PageAlertsLow = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/pageAlertsMedium.js b/src/main/zapHomeFiles/hud/tools/pageAlertsMedium.js
index 94e458fd3..4c3fee740 100644
--- a/src/main/zapHomeFiles/hud/tools/pageAlertsMedium.js
+++ b/src/main/zapHomeFiles/hud/tools/pageAlertsMedium.js
@@ -42,7 +42,7 @@ const PageAlertsMedium = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/scope.js b/src/main/zapHomeFiles/hud/tools/scope.js
index 829ca0951..4670dbb78 100644
--- a/src/main/zapHomeFiles/hud/tools/scope.js
+++ b/src/main/zapHomeFiles/hud/tools/scope.js
@@ -39,20 +39,20 @@ const Scope = (function () {
 			.then(isInScope => {
 				const config = {};
 
-				if (!isInScope) {
-					config.title = LABEL;
-					config.text = DIALOG.OUT;
+				if (isInScope) {
+					config.text = DIALOG.IN;
 					config.buttons = [
-						{text: I18n.t('common_add'),
-							id: 'add'},
+						{text: I18n.t('common_remove'),
+							id: 'remove'},
 						{text: I18n.t('common_cancel'),
 							id: 'cancel'}
 					];
 				} else {
-					config.text = DIALOG.IN;
+					config.title = LABEL;
+					config.text = DIALOG.OUT;
 					config.buttons = [
-						{text: I18n.t('common_remove'),
-							id: 'remove'},
+						{text: I18n.t('common_add'),
+							id: 'add'},
 						{text: I18n.t('common_cancel'),
 							id: 'cancel'}
 					];
@@ -107,7 +107,7 @@ const Scope = (function () {
 						utils.zapApiErrorDialog(tabId, error);
 						throw error;
 					})
-					.then(response => {
+					.then(_response => {
 						utils.messageAllTabs(tool.panel, {action: 'broadcastUpdate', context: {domain}, tool: {name: NAME, data: DATA.IN, icon: ICONS.IN, label: LABEL}});
 						return utils.writeTool(tool);
 					})
@@ -125,7 +125,7 @@ const Scope = (function () {
 				utils.zapApiErrorDialog(tabId, error);
 				throw error;
 			})
-			.then(response => {
+			.then(_response => {
 				// Remove from list and save
 				utils.loadTool(NAME)
 					.then(tool => {
@@ -169,7 +169,7 @@ const Scope = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/showComments.js b/src/main/zapHomeFiles/hud/tools/showComments.js
index 1c46f33a1..d3340937a 100644
--- a/src/main/zapHomeFiles/hud/tools/showComments.js
+++ b/src/main/zapHomeFiles/hud/tools/showComments.js
@@ -46,10 +46,10 @@ const ShowComments = (function () {
 	}
 
 	function switchState(tabId) {
-		if (!loc.isRunning) {
-			switchOn(tabId);
-		} else {
+		if (loc.isRunning) {
 			switchOff(tabId);
+		} else {
+			switchOn(tabId);
 		}
 	}
 
@@ -129,7 +129,7 @@ const ShowComments = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/showEnable.js b/src/main/zapHomeFiles/hud/tools/showEnable.js
index 6b8a816f2..c12138578 100644
--- a/src/main/zapHomeFiles/hud/tools/showEnable.js
+++ b/src/main/zapHomeFiles/hud/tools/showEnable.js
@@ -39,10 +39,10 @@ const ShowEnable = (function () {
 	function switchState() {
 		checkIsRunning()
 			.then(isRunning => {
-				if (!isRunning) {
-					switchOn();
-				} else {
+				if (isRunning) {
 					switchOff();
+				} else {
+					switchOn();
 				}
 			})
 			.catch(utils.errorHandler);
@@ -106,7 +106,7 @@ const ShowEnable = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/siteAlertsHigh.js b/src/main/zapHomeFiles/hud/tools/siteAlertsHigh.js
index 84e415732..c5eb274d8 100644
--- a/src/main/zapHomeFiles/hud/tools/siteAlertsHigh.js
+++ b/src/main/zapHomeFiles/hud/tools/siteAlertsHigh.js
@@ -42,7 +42,7 @@ const SiteAlertsHigh = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/siteAlertsInformational.js b/src/main/zapHomeFiles/hud/tools/siteAlertsInformational.js
index 8c8573c16..96a304109 100644
--- a/src/main/zapHomeFiles/hud/tools/siteAlertsInformational.js
+++ b/src/main/zapHomeFiles/hud/tools/siteAlertsInformational.js
@@ -42,7 +42,7 @@ const SiteAlertsInformational = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/siteAlertsLow.js b/src/main/zapHomeFiles/hud/tools/siteAlertsLow.js
index a91854bcd..7021a5f79 100644
--- a/src/main/zapHomeFiles/hud/tools/siteAlertsLow.js
+++ b/src/main/zapHomeFiles/hud/tools/siteAlertsLow.js
@@ -42,7 +42,7 @@ const SiteAlertsLow = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/siteAlertsMedium.js b/src/main/zapHomeFiles/hud/tools/siteAlertsMedium.js
index 7320dd505..8aabc47c3 100644
--- a/src/main/zapHomeFiles/hud/tools/siteAlertsMedium.js
+++ b/src/main/zapHomeFiles/hud/tools/siteAlertsMedium.js
@@ -42,7 +42,7 @@ const SiteAlertsMedium = (function () {
 		alertUtils.showOptions(tabId, NAME, LABEL);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/siteTree.js b/src/main/zapHomeFiles/hud/tools/siteTree.js
index f11d2d533..985436417 100644
--- a/src/main/zapHomeFiles/hud/tools/siteTree.js
+++ b/src/main/zapHomeFiles/hud/tools/siteTree.js
@@ -53,13 +53,13 @@ const SiteTree = (function () {
 
 	function getTool(port) {
 		utils.loadTool(NAME)
-			.then(tool => {
+			.then(_tool => {
 				port.postMessage({label: LABEL, data: DATA.SITES, icon: ICONS.WORLD});
 			})
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/spider.js b/src/main/zapHomeFiles/hud/tools/spider.js
index b11c823a3..f57c35343 100644
--- a/src/main/zapHomeFiles/hud/tools/spider.js
+++ b/src/main/zapHomeFiles/hud/tools/spider.js
@@ -48,17 +48,15 @@ const Spider = (function () {
 				const config = {};
 				config.buttons = [{text: I18n.t('common_cancel'), id: 'cancel'}];
 
-				if (!isRunning) {
-					if (!isInScope) {
-						config.text = DIALOG.START_ADD_SCOPE_1 + domain + DIALOG.START_ADD_SCOPE_2 + domain + DIALOG.START_ADD_SCOPE_3;
-						config.buttons.unshift({text: I18n.t('common_start'), id: 'start-add-to-scope'});
-					} else {
-						config.text = DIALOG.START_1 + domain + DIALOG.START_2;
-						config.buttons.unshift({text: I18n.t('common_start'), id: 'start'});
-					}
-				} else {
+				if (isRunning) {
 					config.text = DIALOG.STOP_1 + tool.runningScope[0] + DIALOG.STOP_2;
 					config.buttons.unshift({text: I18n.t('common_stop'), id: 'stop'});
+				} else if (isInScope) {
+					config.text = DIALOG.START_1 + domain + DIALOG.START_2;
+					config.buttons.unshift({text: I18n.t('common_start'), id: 'start'});
+				} else {
+					config.text = DIALOG.START_ADD_SCOPE_1 + domain + DIALOG.START_ADD_SCOPE_2 + domain + DIALOG.START_ADD_SCOPE_3;
+					config.buttons.unshift({text: I18n.t('common_start'), id: 'start-add-to-scope'});
 				}
 
 				return config;
@@ -85,7 +83,7 @@ const Spider = (function () {
 	function startSpider(tabId, domain) {
 		utils.getUpgradedDomain(domain)
 			.then(upgradedDomain => {
-				apiCallWithResponse('spider', 'action', 'scan', {url: upgradedDomain}).then(response => {
+				apiCallWithResponse('spider', 'action', 'scan', {url: upgradedDomain}).then(_response => {
 					spiderStarted(tabId, domain);
 				})
 					.catch(error => {
@@ -110,7 +108,7 @@ const Spider = (function () {
 	}
 
 	function stopSpider(tabId) {
-		apiCallWithResponse('spider', 'action', 'stop').then(response => {
+		apiCallWithResponse('spider', 'action', 'stop').then(_response => {
 			spiderStopped(tabId);
 		})
 			.catch(error => {
@@ -118,7 +116,7 @@ const Spider = (function () {
 			});
 	}
 
-	function spiderStopped(tabId) {
+	function spiderStopped(_tabId) {
 		utils.loadTool(NAME)
 			.then(tool => {
 				tool.isRunning = false;
@@ -200,7 +198,7 @@ const Spider = (function () {
 		}
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		// Events up to 2.11.1
 		registerForZapEvents('org.zaproxy.zap.extension.spider.SpiderEventPublisher');
diff --git a/src/main/zapHomeFiles/hud/tools/toggleScript.js b/src/main/zapHomeFiles/hud/tools/toggleScript.js
index adcb3e7ca..a332f690c 100644
--- a/src/main/zapHomeFiles/hud/tools/toggleScript.js
+++ b/src/main/zapHomeFiles/hud/tools/toggleScript.js
@@ -147,7 +147,7 @@ const ToggleScript = (function () {
 			.catch(utils.errorHandler);
 	}
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 	});
 
diff --git a/src/main/zapHomeFiles/hud/tools/utils/alertUtils.js b/src/main/zapHomeFiles/hud/tools/utils/alertUtils.js
index 0b6c9826d..e87cb9e39 100644
--- a/src/main/zapHomeFiles/hud/tools/utils/alertUtils.js
+++ b/src/main/zapHomeFiles/hud/tools/utils/alertUtils.js
@@ -1,3 +1,4 @@
+// eslint-disable-next-line no-unused-vars
 const alertUtils = (function () {
 	function showSiteAlerts(tabId, title, target, alertRisk) {
 		// Note that theres no need to load any tool data here
@@ -39,14 +40,14 @@ const alertUtils = (function () {
 
 	function flattenAlerts(alerts) {
 		const json = {};
-		for (let i = 0; i < alerts.length; i++) {
-			const alert = alerts[i];
+
+		alerts.forEach(alert => {
 			for (const key in alert) {
 				if (Object.prototype.hasOwnProperty.call(alert, key)) {
 					json[key] = alert[key];
 				}
 			}
-		}
+		});
 
 		return json;
 	}
@@ -69,7 +70,7 @@ const alertUtils = (function () {
 
 				if (target.indexOf('?') > 0) {
 					// Remove any url params
-					target = target.substring(0, target.indexOf('?'));
+					target = target.slice(0, target.indexOf('?'));
 				}
 
 				return apiCallWithResponse('alert', 'view', 'alertsByRisk', {url: target, recurse: 'false'});
diff --git a/src/main/zapHomeFiles/hud/tools/websockets.js b/src/main/zapHomeFiles/hud/tools/websockets.js
index 7e16eb46d..25bc558ab 100644
--- a/src/main/zapHomeFiles/hud/tools/websockets.js
+++ b/src/main/zapHomeFiles/hud/tools/websockets.js
@@ -99,7 +99,7 @@ const WebSockets = (function () {
 		}
 	});
 
-	self.addEventListener('activate', event => {
+	self.addEventListener('activate', _event => {
 		initializeStorage();
 		registerForZapEvents('org.zaproxy.zap.extension.websocket.WebSocketEventPublisher');
 	});
diff --git a/src/main/zapHomeFiles/hud/utils.js b/src/main/zapHomeFiles/hud/utils.js
index 5ac5c3184..ce71b533c 100644
--- a/src/main/zapHomeFiles/hud/utils.js
+++ b/src/main/zapHomeFiles/hud/utils.js
@@ -3,8 +3,10 @@ const IS_HUD_INITIALIZED = 'isHudInitialized';
 const IS_FIRST_TIME = 'isFirstTime';
 const IS_SERVICEWORKER_REFRESHED = 'isServiceWorkerRefreshed';
 
+// eslint-disable-next-line no-unused-vars
 const LOG_OFF = 0;	// Just use for setting the level, nothing will be logged
 const LOG_ERROR = 1;	// Errors that should be addressed
+// eslint-disable-next-line no-unused-vars
 const LOG_WARN = 2;	// A potential problem
 const LOG_INFO = 3;	// Significant but infrequent events
 const LOG_DEBUG = 4;	// Relatively fine grain events which can help debug problems
@@ -13,8 +15,7 @@ const LOG_STRS = ['OFF', 'ERROR', 'WARN', 'INFO', 'DEBUG', 'TRACE'];
 
 class NoClientIdError extends Error {}
 
-/* exported utils */
-
+// eslint-disable-next-line no-unused-vars
 const utils = (function () {
 	/*
 	 * Utility Functions
@@ -42,27 +43,27 @@ const utils = (function () {
 	function parseRequestHeader(headerText) {
 		const header = {};
 
-		header.method = headerText.substring(0, headerText.indexOf(' '));
-		headerText = headerText.substring(headerText.indexOf(' ') + 1);
+		header.method = headerText.slice(0, headerText.indexOf(' '));
+		headerText = headerText.slice(headerText.indexOf(' ') + 1);
 
-		header.uri = headerText.substring(0, headerText.indexOf(' '));
-		headerText = headerText.substring(headerText.indexOf(' ') + 1);
+		header.uri = headerText.slice(0, headerText.indexOf(' '));
+		headerText = headerText.slice(headerText.indexOf(' ') + 1);
 
-		header.version = headerText.substring(0, headerText.indexOf('\r'));
-		headerText = headerText.substring(headerText.indexOf('\n') + 1);
+		header.version = headerText.slice(0, headerText.indexOf('\r'));
+		headerText = headerText.slice(headerText.indexOf('\n') + 1);
 
 		header.fields = {};
 		while (headerText !== '') {
-			const field = headerText.substring(0, headerText.indexOf(':'));
-			headerText = headerText.substring(headerText.indexOf(':') + 2);
+			const field = headerText.slice(0, headerText.indexOf(':'));
+			headerText = headerText.slice(headerText.indexOf(':') + 2);
 			let value;
 
-			if (headerText.indexOf('\n') < 0) {
+			if (headerText.includes('\n')) {
+				value = headerText.slice(0, headerText.indexOf('\n'));
+				headerText = headerText.slice(headerText.indexOf('\n') + 1);
+			} else {
 				value = headerText;
 				headerText = '';
-			} else {
-				value = headerText.substring(0, headerText.indexOf('\n'));
-				headerText = headerText.substring(headerText.indexOf('\n') + 1);
 			}
 
 			header.fields[field] = value;
@@ -77,22 +78,22 @@ const utils = (function () {
 	function parseResponseHeader(headerText) {
 		const header = {};
 
-		header.version = headerText.substring(0, headerText.indexOf(' '));
-		headerText = headerText.substring(headerText.indexOf(' ') + 1);
+		header.version = headerText.slice(0, headerText.indexOf(' '));
+		headerText = headerText.slice(headerText.indexOf(' ') + 1);
 
-		header.status = headerText.substring(0, headerText.indexOf(' '));
-		headerText = headerText.substring(headerText.indexOf(' ') + 1);
+		header.status = headerText.slice(0, headerText.indexOf(' '));
+		headerText = headerText.slice(headerText.indexOf(' ') + 1);
 
-		header.reason = headerText.substring(0, headerText.indexOf(' '));
-		headerText = headerText.substring(headerText.indexOf(' ') + 1);
+		header.reason = headerText.slice(0, headerText.indexOf(' '));
+		headerText = headerText.slice(headerText.indexOf(' ') + 1);
 
 		header.fields = {};
 		while (headerText !== '') {
-			const field = headerText.substring(0, headerText.indexOf(':'));
-			headerText = headerText.substring(headerText.indexOf(':') + 2);
+			const field = headerText.slice(0, headerText.indexOf(':'));
+			headerText = headerText.slice(headerText.indexOf(':') + 2);
 
-			const value = headerText.substring(0, headerText.indexOf('\n'));
-			headerText = headerText.substring(headerText.indexOf('\n') + 1);
+			const value = headerText.slice(0, headerText.indexOf('\n'));
+			headerText = headerText.slice(headerText.indexOf('\n') + 1);
 
 			header.fields[field] = value;
 		}
@@ -124,7 +125,7 @@ const utils = (function () {
 	}
 
 	function hasScheme(url) {
-		return url.indexOf('://') > -1;
+		return url.includes('://');
 	}
 
 	/*
@@ -135,7 +136,7 @@ const utils = (function () {
 		let end = url.indexOf('&', start);
 		end = end === -1 ? url.length : end;
 
-		return url.substring(start, end);
+		return url.slice(start, end);
 	}
 
 	/* STORAGE */
@@ -151,7 +152,7 @@ const utils = (function () {
 	 * Initialize all of the info that will be stored in indexeddb.
 	 */
 	function initializeHUD(leftTools, rightTools, drawer) {
-		if (IS_DEV_MODE && leftTools.indexOf('hudErrors') < 0) {
+		if (IS_DEV_MODE && !leftTools.includes('hudErrors')) {
 			// Always add the error tool in dev mode
 			leftTools.push('hudErrors');
 		}
@@ -194,8 +195,8 @@ const utils = (function () {
 	function setDefaultTools(leftTools, rightTools) {
 		const promises = [];
 
-		for (let i = 0; i < leftTools.length; i++) {
-			loadTool(leftTools[i])
+		leftTools.forEach((leftTool, i) => {
+			loadTool(leftTool)
 				.then(tool => {
 					if (!tool) {
 						log(LOG_ERROR, 'utils.setDefaultTools', 'Failed to load tool.', tool.name);
@@ -209,10 +210,10 @@ const utils = (function () {
 					return writeTool(tool);
 				})
 				.catch(errorHandler);
-		}
+		});
 
-		for (let i = 0; i < rightTools.length; i++) {
-			loadTool(rightTools[i])
+		rightTools.forEach((rightTool, i) => {
+			loadTool(rightTool)
 				.then(tool => {
 					if (!tool) {
 						log(LOG_ERROR, 'utils.setDefaultTools', 'Failed to load tool.', tool.name);
@@ -226,7 +227,7 @@ const utils = (function () {
 					return writeTool(tool);
 				})
 				.catch(errorHandler);
-		}
+		});
 
 		return Promise.all(promises);
 	}
@@ -429,8 +430,7 @@ const utils = (function () {
 	function messageFrame(tabId, frameId, message) {
 		return clients.matchAll({includeUncontrolled: true})
 			.then(clients => {
-				for (let i = 0; i < clients.length; i++) {
-					const client = clients[i];
+				clients.forEach(client => {
 					const parameters = new URL(client.url).searchParams;
 
 					const tid = parameters.get('tabId');
@@ -439,7 +439,7 @@ const utils = (function () {
 					if (tid === tabId && fid === frameId) {
 						return client;
 					}
-				}
+				});
 
 				throw new NoClientIdError('Could not find a ClientId for tabId: ' + tabId + ', frameId: ' + frameId);
 			})
@@ -468,8 +468,7 @@ const utils = (function () {
 			.then(clients => {
 				const frameClients = [];
 
-				for (let i = 0; i < clients.length; i++) {
-					const client = clients[i];
+				clients.forEach(client => {
 					const parameters = new URL(client.url).searchParams;
 
 					const fid = parameters.get('frameId');
@@ -477,7 +476,7 @@ const utils = (function () {
 					if (fid === frameId) {
 						frameClients.push(client);
 					}
-				}
+				});
 
 				if (frameClients.length === 0) {
 					log(LOG_DEBUG, 'utils.messageAllTabs', 'Could not find any clients for frameId: ' + frameId, message);
@@ -488,9 +487,7 @@ const utils = (function () {
 			})
 			.then(clients => {
 				return new Promise(((resolve, reject) => {
-					for (let i = 0; i < clients.length; i++) {
-						const client = clients[i];
-
+					clients.forEach(client => {
 						const channel = new MessageChannel();
 						channel.port1.start();
 						channel.port2.start();
@@ -504,7 +501,7 @@ const utils = (function () {
 						});
 
 						client.postMessage(message, [channel.port2]);
-					}
+					});
 				}));
 			})
 			.catch(errorHandler);
@@ -523,8 +520,7 @@ const utils = (function () {
 			.then(clients => {
 				const frameClients = [];
 
-				for (let i = 0; i < clients.length; i++) {
-					const client = clients[i];
+				clients.forEach(client => {
 					const parameters = new URL(client.url).searchParams;
 
 					const fid = parameters.get('frameId');
@@ -532,7 +528,7 @@ const utils = (function () {
 					if (fid === frameId) {
 						frameClients.push(client);
 					}
-				}
+				});
 
 				return frameClients;
 			})
@@ -654,7 +650,7 @@ const utils = (function () {
 					scheme = 'http';
 				}
 
-				return scheme + '://' + domain + url.substring(url.indexOf(domain) + domain.length);
+				return scheme + '://' + domain + url.slice(url.indexOf(domain) + domain.length);
 			})
 			.catch(errorHandler);
 	}
@@ -669,8 +665,8 @@ const utils = (function () {
 			// Construct the stack trace
 			const lines = error.stack.split('\n').slice(0, -1);
 			lines.forEach(line => {
-				const functionName = line.substring(0, line.indexOf('/'));
-				const urlAndLineNo = line.substring(line.indexOf('http'), line.length - 1);
+				const functionName = line.slice(0, line.indexOf('/'));
+				const urlAndLineNo = line.slice(line.indexOf('http'), -1);
 				const parts = urlAndLineNo.split(':');
 				let url = parts[0] + ':' + parts[1];
 				let lineNo = parts[2] + ':' + parts[3];