diff --git a/README.md b/README.md
index 2edf1bf..5b16c7e 100644
--- a/README.md
+++ b/README.md
@@ -28,6 +28,7 @@ KeePassXC-Browser extension requests the following permissions:
 | ----- | ----- |
 | `activeTab`               | To get URL of the current tab |
 | `contextMenus`            | To show context menu items |
+| `cookies`                 | To access browser's internal Public Suffix List |
 | `clipboardWrite`          | Allows password to be copied from password generator to clipboard |
 | `nativeMessaging`         | Allows communication with KeePassXC application |
 | `notifications`           | To show browser notifications |
@@ -42,7 +43,7 @@ KeePassXC-Browser extension requests the following permissions:
 
 ## Protocol
 
-The details about the messaging protocol used with the browser extension and KeePassXC can be found [here](keepassxc-protocol.md).
+Check [keepassxc-protocol](keepassxc-protocol.md) for the details about the messaging protocol used between the browser extension and KeePassXC.
 
 ## Translations
 
diff --git a/keepassxc-browser/_locales/en/messages.json b/keepassxc-browser/_locales/en/messages.json
index 1e1ecc9..b6140ee 100644
--- a/keepassxc-browser/_locales/en/messages.json
+++ b/keepassxc-browser/_locales/en/messages.json
@@ -387,6 +387,10 @@
         "message": "Add Username-only option for the site",
         "description": "Button text for adding Username-only option."
     },
+    "popupAllowIframeButton": {
+        "message": "Allow Cross-Origin iframes for the site",
+        "description": "Button text for allowing Cross-Origin iframes option."
+    },
     "popupErrorEncountered": {
         "message": "KeePassXC-Browser has encountered an error:",
         "description": "A text shown above error message in the popup."
@@ -447,6 +451,10 @@
         "message": "Only a single username field was detected. Add the URL to Site Preferences with Username-only option enabled?",
         "description": "Text shown when page can be added to Site Preferences with Username-only option enabled."
     },
+    "popupIframeDetected": {
+        "message": "A Cross-Origin iframe was detected. Add the URL to Site Preferences with Allow Cross-Origin iframes option enabled?",
+        "description": "Text shown when page can be added to Site Preferences with Allow Cross-Origin iframes option enabled."
+    },
     "rememberInfoText": {
         "message": "Username or password changed! Save it?",
         "description": "Message when username or password has changed."
@@ -1015,6 +1023,10 @@
         "message": "Improved Input Field Detection",
         "description": "Improved Input Field Detection column text."
     },
+    "optionsColumnAllowIframes": {
+        "message": "Allow Cross-Origin iframes",
+        "description": "Allow iframes column text."
+  },
     "optionsColumnDelete": {
         "message": "Delete",
         "description": "Site preferences list column title."
@@ -1135,6 +1147,10 @@
         "message": "Improved Input Field Detection allows more detailed dynamic input field detection. However, it might affect the page performance. Use with caution.",
         "description": "Improved Input Field Detection help text."
     },
+    "optionsSitePreferencesAllowIframesHelpText": {
+        "message": "Allowing Cross-Origin iframes will enable credential retrieval for iframes from another domain. Use at your own risk.",
+        "description": "Allow Cross-Origin iframes help text."
+    },
     "optionsSitePreferencesManualAddText": {
         "message": "Add URL manually",
         "description": "Label for adding site manually on Site preferences tab."
diff --git a/keepassxc-browser/background/event.js b/keepassxc-browser/background/event.js
index 06e4625..ebb197b 100755
--- a/keepassxc-browser/background/event.js
+++ b/keepassxc-browser/background/event.js
@@ -26,18 +26,21 @@ kpxcEvent.showStatus = async function(tab, configured, internalPoll) {
 
     const errorMessage = page.tabs[tab.id]?.errorMessage ?? undefined;
     const usernameFieldDetected = page.tabs[tab.id]?.usernameFieldDetected ?? false;
+    const iframeDetected = page.tabs[tab.id]?.iframeDetected ?? false;
 
     return {
-        identifier: keyId,
+        associated: keepass.isAssociated(),
+
         configured: configured,
         databaseClosed: keepass.isDatabaseClosed,
-        keePassXCAvailable: keepass.isKeePassXCAvailable,
         encryptionKeyUnrecognized: keepass.isEncryptionKeyUnrecognized,
-        associated: keepass.isAssociated(),
         error: errorMessage,
-        usernameFieldDetected: usernameFieldDetected,
+        iframeDetected: iframeDetected,
+        identifier: keyId,
+        keePassXCAvailable: keepass.isKeePassXCAvailable,
         showGettingStartedGuideAlert: page.settings.showGettingStartedGuideAlert,
-        showTroubleshootingGuideAlert: page.settings.showTroubleshootingGuideAlert
+        showTroubleshootingGuideAlert: page.settings.showTroubleshootingGuideAlert,
+        usernameFieldDetected: usernameFieldDetected
     };
 };
 
@@ -177,6 +180,10 @@ kpxcEvent.onUsernameFieldDetected = async function(tab, detected) {
     page.tabs[tab.id].usernameFieldDetected = detected;
 };
 
+kpxcEvent.onIframeDetected = async function(tab, detected) {
+    page.tabs[tab.id].iframeDetected = detected;
+};
+
 kpxcEvent.passwordGetFilled = async function() {
     return page.passwordFilled;
 };
@@ -251,8 +258,10 @@ kpxcEvent.messageHandlers = {
     'get_totp': keepass.getTotp,
     'hide_getting_started_guide_alert': kpxcEvent.hideGettingStartedGuideAlert,
     'hide_troubleshooting_guide_alert': kpxcEvent.hideTroubleshootingGuideAlert,
+    'iframe_detected': kpxcEvent.onIframeDetected,
     'init_http_auth': kpxcEvent.initHttpAuth,
     'is_connected': kpxcEvent.getIsKeePassXCAvailable,
+    'is_iframe_allowed': page.isIframeAllowed,
     'load_keyring': kpxcEvent.onLoadKeyRing,
     'load_settings': kpxcEvent.onLoadSettings,
     'lock_database': kpxcEvent.lockDatabase,
@@ -263,6 +272,7 @@ kpxcEvent.messageHandlers = {
     'page_get_manual_fill': page.getManualFill,
     'page_get_redirect_count': kpxcEvent.pageGetRedirectCount,
     'page_get_submitted': page.getSubmitted,
+    'page_set_allow_iframes': page.setAllowIframes,
     'page_set_autosubmit_performed': page.setAutoSubmitPerformed,
     'page_set_login_id': page.setLoginId,
     'page_set_manual_fill': page.setManualFill,
diff --git a/keepassxc-browser/background/keepass.js b/keepassxc-browser/background/keepass.js
index cc50daa..0db8141 100755
--- a/keepassxc-browser/background/keepass.js
+++ b/keepassxc-browser/background/keepass.js
@@ -582,7 +582,7 @@ keepass.requestAutotype = async function(tab, args = []) {
 
     const kpAction = kpActions.REQUEST_AUTOTYPE;
     const nonce = keepassClient.getNonce();
-    const search = getTopLevelDomainFromUrl(args[0]);
+    const search = page.getTopLevelDomainFromUrl(args[0]);
 
     const messageData = {
         action: kpAction,
diff --git a/keepassxc-browser/background/page.js b/keepassxc-browser/background/page.js
index d7c7495..861f7d6 100755
--- a/keepassxc-browser/background/page.js
+++ b/keepassxc-browser/background/page.js
@@ -155,6 +155,7 @@ page.clearLogins = function(tabId) {
         return;
     }
 
+    page.tabs[tabId].allowIframes = false;
     page.tabs[tabId].credentials = [];
     page.tabs[tabId].loginList = [];
     page.currentRequest = {};
@@ -186,6 +187,7 @@ page.clearSubmittedCredentials = async function() {
 
 page.createTabEntry = function(tabId) {
     page.tabs[tabId] = {
+        allowIframes: false,
         credentials: [],
         errorMessage: null,
         loginList: [],
@@ -330,6 +332,101 @@ page.updatePopup = function(tab) {
     browserAction.showDefault(tab);
 };
 
+page.setAllowIframes = async function(tab, args = []) {
+    const [ allowIframes, site ] = args;
+
+    // Only set when main windows' URL is used
+    if (tab?.url === site) {
+        page.tabs[tab.id].allowIframes = allowIframes;
+    }
+};
+
+page.isIframeAllowed = async function(tab, args = []) {
+    const [ url, hostname ] = args;
+    const baseDomain = await page.getBaseDomainFromUrl(hostname, url);
+
+    // Allow if exception has been set from Site Preferences
+    if (page.tabs[tab.id]?.allowIframes) {
+        return true;
+    }
+
+    // Allow iframe if the base domain is included in iframes' and tab's hostname
+    const tabUrl = new URL(tab?.url);
+    return hostname.endsWith(baseDomain) && tabUrl.hostname?.endsWith(baseDomain);
+};
+
+/**
+ * Gets the top level domain from URL.
+ * @param {string} domain   Current iframe's hostname
+ * @param {string} url      Current iframe's full URL
+ * @returns {string}        TLD e.g. https://another.example.co.uk -> co.uk
+ */
+page.getTopLevelDomainFromUrl = async function(domain, url) {
+    // A simple check for IPv4 address. TLD cannot be numeric, and if hostname is just numbers, it's probably an IPv4.
+    // TODO: Handle IPv6 addresses. Is there some internal API for these?
+    if (!isNaN(Number(domain?.replaceAll('.', '')))) {
+        return domain;
+    }
+
+    // Only loop the amount of different domain parts found
+    const numberOfDomainParts = domain?.split('.')?.length;
+    for (let i = 0; i < numberOfDomainParts; ++i) {
+        // Cut the first part from host
+        const index = domain?.indexOf('.');
+        if (index < 0) {
+            continue;
+        }
+
+        // Check if dummy cookie's domain/TLD matches with public suffix list.
+        // If setting the cookie fails, TLD has been found.
+        try {
+            domain = domain?.substring(index + 1);
+            const reply = await browser.cookies.set({
+                domain: domain,
+                name: 'kpxc',
+                sameSite: 'strict',
+                url: url,
+                value: ''
+            });
+
+            // Delete the temporary cookie immediately
+            if (reply) {
+                await browser.cookies.remove({
+                    name: 'kpxc',
+                    url: url
+                });
+            }
+        } catch (e) {
+            return domain;
+        }
+    }
+
+    return domain;
+};
+
+/**
+ * Gets the base domain of URL or hostname.
+ * Up-to-date list can be found: https://publicsuffix.org/list/public_suffix_list.dat
+ * @param {string} domain   Current iframe's hostname
+ * @param {string} url      Current iframe's full URL
+ * @returns {string}        The base domain, e.g. https://another.example.co.uk -> example.co.uk
+ */
+page.getBaseDomainFromUrl = async function(hostname, url) {
+    const tld = await page.getTopLevelDomainFromUrl(hostname, url);
+    if (tld.length === 0 || tld === hostname) {
+        return hostname;
+    }
+
+    // Remove the top level domain part from the hostname, e.g. https://another.example.co.uk -> https://another.example
+    const finalDomain = hostname.slice(0, hostname.indexOf(tld) - 1);
+    // Split the URL and select the last part, e.g. https://another.example -> example
+    let baseDomain = finalDomain.split('.')?.at(-1);
+    // Append the top level domain back to the URL, e.g. example -> example.co.uk
+    baseDomain = baseDomain + '.' + tld;
+
+    return baseDomain;
+};
+
 const createContextMenuItem = function({ action, args, ...options }) {
     return browser.contextMenus.create({
         contexts: menuContexts,
@@ -345,6 +442,7 @@ const createContextMenuItem = function({ action, args, ...options }) {
     });
 };
 
+
 const logDebug = function(message, extra) {
     if (page.settings.debugLogging) {
         debugLogMessage(message, extra);
diff --git a/keepassxc-browser/common/global.js b/keepassxc-browser/common/global.js
index fe84b65..43e2c55 100755
--- a/keepassxc-browser/common/global.js
+++ b/keepassxc-browser/common/global.js
@@ -111,19 +111,6 @@ const slashNeededForUrl = function(pattern) {
     return matchPattern.exec(pattern);
 };
 
-// Returns the top level domain, e.g. https://another.example.co.uk -> example.co.uk
-// This is done because a top level domain will probably give better matches with Auto-Type than a full hostname.
-const getTopLevelDomainFromUrl = function(hostname) {
-    const domainRegex = new RegExp(/(\w+).(com|net|org|edu|co)*(.\w+)$/g);
-    const domainMatch = domainRegex.exec(hostname);
-
-    if (domainMatch) {
-        return domainMatch[0];
-    }
-
-    return hostname;
-};
-
 function tr(key, params) {
     return browser.i18n.getMessage(key, params);
 }
diff --git a/keepassxc-browser/content/keepassxc-browser.js b/keepassxc-browser/content/keepassxc-browser.js
index 3c60bb2..4e82495 100755
--- a/keepassxc-browser/content/keepassxc-browser.js
+++ b/keepassxc-browser/content/keepassxc-browser.js
@@ -27,8 +27,8 @@ kpxc.singleInputEnabledForPage = false;
 kpxc.submitUrl = null;
 kpxc.url = null;
 
-// Add page to Site Preferences with Username-only detection enabled. Set from the popup
-kpxc.addToSitePreferences = async function() {
+// Add page to Site Preferences with a selected option enabled. Set from the popup.
+kpxc.addToSitePreferences = async function(optionName, addWildcard = false) {
     // Returns a predefined URL for certain sites
     let site = trimURL(window.top.location.href).toLowerCase();
 
@@ -37,24 +37,32 @@ kpxc.addToSitePreferences = async function() {
     for (const existingSite of kpxc.settings['sitePreferences']) {
         if (existingSite.url === site) {
             existingSite.ignore = IGNORE_NOTHING;
-            existingSite.usernameOnly = true;
+            existingSite[optionName] = true;
             siteExists = true;
         }
     }
 
     if (!siteExists) {
         // Add wildcard to the URL
-        site = site.slice(0, site.lastIndexOf('/') + 1) + '*';
+        if (addWildcard) {
+            site = site.slice(0, site.lastIndexOf('/') + 1) + '*';
+        }
 
         kpxc.settings['sitePreferences'].push({
             url: site,
             ignore: IGNORE_NOTHING,
-            usernameOnly: true
+            [optionName]: true
         });
     }
 
     await sendMessage('save_settings', kpxc.settings);
-    sendMessage('username_field_detected', false);
+
+    if (optionName === 'allowIframes') {
+        await sendMessage('page_set_allow_iframes', [ true, site ]);
+        await sendMessage('iframe_detected', false);
+    } else if (optionName === 'usernameOnly') {
+        await sendMessage('username_field_detected', false);
+    }
 };
 
 // Clears all from the content and background scripts, including autocomplete
@@ -584,7 +592,7 @@ kpxc.rememberCredentialsFromContextMenu = async function() {
 // The basic function for retrieving credentials from KeePassXC.
 // Credential Banner can force the retrieval for reloading new/modified credentials.
 kpxc.retrieveCredentials = async function(force = false) {
-    if (!isIframeAllowed()) {
+    if (!await isIframeAllowed()) {
         return [];
     }
 
@@ -623,7 +631,7 @@ kpxc.retrieveCredentialsCallback = async function(credentials) {
 // If credentials are not received, request them again
 kpxc.receiveCredentialsIfNecessary = async function() {
     if (kpxc.credentials.length === 0 && !_called.retrieveCredentials) {
-        if (!isIframeAllowed()) {
+        if (!await isIframeAllowed()) {
             return [];
         }
 
@@ -710,6 +718,7 @@ kpxc.siteIgnored = async function(condition) {
             currentLocation = window.self.location.href.toLowerCase();
         }
 
+        // Refresh current settings for the site
         const currentSetting = condition || IGNORE_FULL;
         for (const site of kpxc.settings.sitePreferences) {
             if (siteMatch(site.url, currentLocation) || site.url === currentLocation) {
@@ -719,6 +728,7 @@ kpxc.siteIgnored = async function(condition) {
 
                 kpxc.singleInputEnabledForPage = site.usernameOnly;
                 kpxc.improvedFieldDetectionEnabledForPage = site.improvedFieldDetection;
+                await sendMessage('page_set_allow_iframes', [ site.allowIframes, currentLocation ]);
             }
         }
 
@@ -901,8 +911,10 @@ browser.runtime.onMessage.addListener(async function(req, sender) {
 
         if (req.action === 'activated_tab') {
             kpxc.triggerActivatedTab();
+        } else if (req.action === 'add_allow_iframes_option') {
+            kpxc.addToSitePreferences('allowIframes');
         } else if (req.action === 'add_username_only_option') {
-            kpxc.addToSitePreferences();
+            kpxc.addToSitePreferences('usernameOnly', true);
         } else if (req.action === 'check_database_hash' && 'hash' in req) {
             kpxc.detectDatabaseChange(req);
         } else if (req.action === 'choose_credential_fields') {
@@ -972,13 +984,21 @@ kpxc.reconnect = async function() {
     return true;
 };
 
-// Check for Cross-domain security error when inspecting window.top.location.href
-const isIframeAllowed = function() {
+const isIframeAllowed = async function() {
+    sendMessage('iframe_detected', false);
     try {
+        // Check for Cross-domain security error when inspecting window.top.location.href
         const currentLocation = window.top.location.href;
         return true;
     } catch (err) {
+        // Inspect iframe using TLD and the tab's original URL
+        const allowed = await sendMessage('is_iframe_allowed', [ window.location.href, window.location.hostname ]);
+        if (allowed) {
+            return true;
+        }
+
         logDebug(`Error: Credential request ignored from another domain: ${window.self.location.host}`);
+        sendMessage('iframe_detected', true);
         return false;
     }
 };
diff --git a/keepassxc-browser/manifest.json b/keepassxc-browser/manifest.json
index 655be6d..d52670f 100755
--- a/keepassxc-browser/manifest.json
+++ b/keepassxc-browser/manifest.json
@@ -145,6 +145,7 @@
     "permissions": [
         "activeTab",
         "contextMenus",
+        "cookies",
         "clipboardWrite",
         "nativeMessaging",
         "notifications",
diff --git a/keepassxc-browser/options/options.css b/keepassxc-browser/options/options.css
index 77f3bd2..da74ffe 100644
--- a/keepassxc-browser/options/options.css
+++ b/keepassxc-browser/options/options.css
@@ -128,6 +128,7 @@ table tbody tr.empty:not(:nth-last-child(2)) {
 
 #tab-site-preferences td:nth-of-type(3),
 #tab-site-preferences td:nth-of-type(4),
+#tab-site-preferences td:nth-of-type(5),
 table td:last-of-type {
     width: 1px;
 }
diff --git a/keepassxc-browser/options/options.html b/keepassxc-browser/options/options.html
index 6134aa4..bee629c 100644
--- a/keepassxc-browser/options/options.html
+++ b/keepassxc-browser/options/options.html
@@ -69,7 +69,7 @@
             </ul>
           </div>
           <footer class="px-3 mt-4 mb-1 text-uppercase position-absolute small text-muted">
-            © 2017-2023 - KeePassXC Team
+            © 2017-2024 - KeePassXC Team
           </footer>
         </nav>
 
@@ -695,6 +695,7 @@
                       <li><span data-i18n="optionsSitePreferencesTabHelpTextThird"></span></li>
                       <li><span data-i18n="optionsSitePreferencesTabHelpTextFourth"></span></li>
                       <li><span data-i18n="optionsSitePreferencesImprovedInputFieldDetectionHelpText"></span></li>
+                      <li><span data-i18n="optionsSitePreferencesAllowIframesHelpText"></span></li>
                     </ul>
                   </div>
                   <hr class="mt-0">
@@ -720,6 +721,7 @@
                           <th scope="col"><span data-i18n="optionsColumnIgnore"></span></th>
                           <th scope="col"><span data-i18n="optionsColumnUsernameOnly"></span></th>
                           <th scope="col"><span data-i18n="optionsColumnImprovedInputFieldDetection"></span></th>
+                          <th scope="col"><span data-i18n="optionsColumnAllowIframes"></span></th>
                           <th scope="col"><span data-i18n="optionsColumnDelete"></span></th>
                         </tr>
                       </thead>
@@ -739,6 +741,7 @@
                           </td>
                           <td><input class="form-check-input" type="checkbox" name="usernameOnly" value="false" data-i18n="[title]optionsColumnUsernameOnly"></td>
                           <td><input class="form-check-input" type="checkbox" name="improvedFieldDetection" value="false" data-i18n="[title]optionsColumnImprovedInputFieldDetection"></td>
+                          <td><input class="form-check-input" type="checkbox" name="allowIframes" value="false" data-i18n="[title]optionsColumnAllowIframes"></td>
                           <td class="text-nowrap">
                             <button class="btn btn-sm delete btn-danger btn">
                               <i class="fa fa-remove" aria-hidden="true"></i>
diff --git a/keepassxc-browser/options/options.js b/keepassxc-browser/options/options.js
index 4cbe9a4..4b80aa7 100644
--- a/keepassxc-browser/options/options.js
+++ b/keepassxc-browser/options/options.js
@@ -395,8 +395,12 @@ options.initConnectedDatabases = function() {
         row.setAttribute('hash', hash);
         row.setAttribute('id', 'tr-cd-' + hash);
 
-        const lastUsed = (options.keyRing[hash].lastUsed) ? new Date(options.keyRing[hash].lastUsed).toLocaleString() : 'unknown';
-        const date = (options.keyRing[hash].created) ? new Date(options.keyRing[hash].created).toLocaleDateString() : 'unknown';
+        const lastUsed = options.keyRing[hash].lastUsed
+            ? new Date(options.keyRing[hash].lastUsed).toLocaleString()
+            : 'unknown';
+        const date = options.keyRing[hash].created
+            ? new Date(options.keyRing[hash].created).toLocaleDateString()
+            : 'unknown';
 
         row.children[0].textContent = options.keyRing[hash].id;
         row.children[1].textContent = options.getPartiallyHiddenKey(options.keyRing[hash].key);
@@ -513,6 +517,8 @@ options.initSitePreferences = function() {
                     site.usernameOnly = this.checked;
                 } else if (this.name === 'improvedFieldDetection') {
                     site.improvedFieldDetection = this.checked;
+                } else if (this.name === 'allowIframes') {
+                    site.allowIframes = this.checked;
                 }
             }
         }
@@ -533,7 +539,7 @@ options.initSitePreferences = function() {
         options.saveSettings();
     };
 
-    const addNewRow = function(rowClone, newIndex, url, ignore, usernameOnly, improvedFieldDetection) {
+    const addNewRow = function(rowClone, newIndex, url, ignore, usernameOnly, improvedFieldDetection, allowIframes) {
         const row = rowClone.cloneNode(true);
         row.setAttribute('url', url);
         row.setAttribute('id', 'tr-scf' + newIndex);
@@ -544,7 +550,9 @@ options.initSitePreferences = function() {
         row.children[2].children['usernameOnly'].addEventListener('change', checkboxClicked);
         row.children[3].children['improvedFieldDetection'].checked = improvedFieldDetection;
         row.children[3].children['improvedFieldDetection'].addEventListener('change', checkboxClicked);
-        row.children[4].addEventListener('click', removeButtonClicked);
+        row.children[4].children['allowIframes'].checked = allowIframes;
+        row.children[4].children['allowIframes'].addEventListener('change', checkboxClicked);
+        row.children[5].addEventListener('click', removeButtonClicked);
 
         $('#tab-site-preferences table tbody').append(row);
     };
@@ -604,10 +612,16 @@ options.initSitePreferences = function() {
         const rowClone = $('#tab-site-preferences table tr.clone').cloneNode(true);
         rowClone.classList.remove('clone', 'd-none');
 
-        addNewRow(rowClone, newIndex, value, IGNORE_NOTHING, false, false);
+        addNewRow(rowClone, newIndex, value, IGNORE_NOTHING, false, false, false);
         $('#tab-site-preferences table tbody tr.empty').hide();
 
-        options.settings['sitePreferences'].push({ url: value, ignore: IGNORE_NOTHING, usernameOnly: false, improvedFieldDetection: false });
+        options.settings['sitePreferences'].push({
+            url: value,
+            ignore: IGNORE_NOTHING,
+            usernameOnly: false,
+            improvedFieldDetection: false,
+            allowIframes: false,
+        });
         options.saveSettings();
         manualUrl.value = '';
     });
@@ -617,7 +631,15 @@ options.initSitePreferences = function() {
     let counter = 1;
     if (options.settings['sitePreferences']) {
         for (const site of options.settings['sitePreferences']) {
-            addNewRow(rowClone, counter, site.url, site.ignore, site.usernameOnly, site.improvedFieldDetection);
+            addNewRow(
+                rowClone,
+                counter,
+                site.url,
+                site.ignore,
+                site.usernameOnly,
+                site.improvedFieldDetection,
+                site.allowIframes,
+            );
             ++counter;
         }
     }
diff --git a/keepassxc-browser/popups/popup.html b/keepassxc-browser/popups/popup.html
index 45a01da..567fd1c 100644
--- a/keepassxc-browser/popups/popup.html
+++ b/keepassxc-browser/popups/popup.html
@@ -130,6 +130,17 @@
           </button>
         </div>
       </div>
+
+      <div id="iframe-detected" style="display: none">
+        <hr>
+        <p data-i18n="popupIframeDetected"></p>
+        <div class="right-align">
+          <button id="allow-iframe-button" class="btn btn-sm btn-primary">
+            <i class="fa fa-plus" aria-hidden="true"></i>
+            <span data-i18n="popupAllowIframeButton"></span>
+          </button>
+        </div>
+      </div>
     </div>
   </body>
 </html>
diff --git a/keepassxc-browser/popups/popup.js b/keepassxc-browser/popups/popup.js
index 3523cf3..2823284 100644
--- a/keepassxc-browser/popups/popup.js
+++ b/keepassxc-browser/popups/popup.js
@@ -57,6 +57,10 @@ function statusResponse(r) {
             $('#username-field-detected').show();
         }
 
+        if (r.iframeDetected) {
+            $('#iframe-detected').show();
+        }
+
         reloadCount = 0;
     }
 }
@@ -137,6 +141,12 @@ const sendMessageToTab = async function(message) {
         $('#username-field-detected').hide();
     });
 
+    $('#allow-iframe-button').addEventListener('click', async () => {
+        await sendMessageToTab('add_allow_iframes_option');
+        await sendMessageToTab('redetect_fields');
+        $('#iframe-detected').hide();
+    });
+
     $('#getting-started-alert-close-button').addEventListener('click', async () => {
         await browser.runtime.sendMessage({
             action: 'hide_getting_started_guide_alert'
diff --git a/tests/tests.js b/tests/tests.js
index ed69f32..2185117 100644
--- a/tests/tests.js
+++ b/tests/tests.js
@@ -72,19 +72,43 @@ async function testGeneral() {
         assertRegex(siteMatch(m[0], m[1]), m[2], testCard, `siteMatch() for ${m[1]}`);
     }
 
-    // Base domain parsing (window.location.hostname)
+    // TODO: Enable these tests later. Not sure how to tests cookies API which requires to be running in the
+    //       background script.
+    // Top-Level-Domain tests
+    /*const tldUrls = [
+        [ 'another.example.co.uk', 'co.uk' ],
+        [ 'www.example.com', 'com' ],
+        [ 'github.com', 'com' ],
+        [ 'test.net', 'net' ],
+        [ 'so.many.subdomains.co.jp', 'co.jp' ],
+        [ '192.168.0.1', '192.168.0.1' ],
+        [ 'www.nic.ar','ar' ],
+        [ 'no.no.no', 'no' ],
+        [ 'www.blogspot.com.ar', 'blogspot.com.ar' ], // blogspot.com.ar is a TLD
+        [ 'jap.an.ide.kyoto.jp', 'ide.kyoto.jp' ], // ide.kyoto.jp is a TLD
+    ];
+
+    for (const d of tldUrls) {
+        kpxcAssert(page.getTopLevelDomainFromUrl(d[0]), d[1], testCard, 'getTopLevelDomainFromUrl() for ' + d[0]);
+    }
+
+    // Base domain tests
     const domains = [
         [ 'another.example.co.uk', 'example.co.uk' ],
         [ 'www.example.com', 'example.com' ],
         [ 'test.net', 'test.net' ],
         [ 'so.many.subdomains.co.jp', 'subdomains.co.jp' ],
-        [ 'test.site.example.com.au', 'example.com.au' ],
-        [ '192.168.0.1', '192.168.0.1' ]
+        [ '192.168.0.1', '192.168.0.1' ],
+        [ 'www.nic.ar', 'nic.ar' ],
+        [ 'www.blogspot.com.ar', 'www.blogspot.com.ar' ], // blogspot.com.ar is a TLD
+        [ 'www.arpa', 'www.arpa' ],
+        [ 'jap.an.ide.kyoto.jp', 'an.ide.kyoto.jp' ], // ide.kyoto.jp is a TLD
+        [ 'kobe.jp', 'kobe.jp' ],
     ];
 
     for (const d of domains) {
-        kpxcAssert(getTopLevelDomainFromUrl(d[0]), d[1], testCard, 'getBaseDomainFromUrl() for ' + d[0]);
-    }
+        kpxcAssert(page.getBaseDomainFromUrl(d[0]), d[1], testCard, 'getBaseDomainFromUrl() for ' + d[0]);
+    }*/
 }
 
 // Input field matching (keepassxc-browser.js)