diff --git a/keepassxc-browser/background/browserAction.js b/keepassxc-browser/background/browserAction.js
index d2fdb7d..4a5e7e0 100755
--- a/keepassxc-browser/background/browserAction.js
+++ b/keepassxc-browser/background/browserAction.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const browserAction = {};
 
 const BLINK_TIMEOUT_DEFAULT = 7500;
diff --git a/keepassxc-browser/background/event.js b/keepassxc-browser/background/event.js
index e4fe61e..de3e6e9 100755
--- a/keepassxc-browser/background/event.js
+++ b/keepassxc-browser/background/event.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const kpxcEvent = {};
 
 kpxcEvent.onMessage = function(request, sender, callback) {
@@ -264,19 +266,10 @@ kpxcEvent.pageClearLogins = function(callback, tab, alreadyCalled) {
     callback();
 };
 
-kpxcEvent.oldDatabaseHash = 'no-hash';
-kpxcEvent.checkDatabaseHash = function(callback, tab) {
-    keepass.checkDatabaseHash((response) => {
-        callback({old: kpxcEvent.oldDatabaseHash, new: response});
-        kpxcEvent.oldDatabaseHash = response;
-    });
-};
-
 // all methods named in this object have to be declared BEFORE this!
 kpxcEvent.messageHandlers = {
     'add_credentials': keepass.addCredentials,
     'associate': keepass.associate,
-    'check_databasehash': kpxcEvent.checkDatabaseHash,
     'check_update_keepassxc': kpxcEvent.onCheckUpdateKeePassXC,
     'generate_password': keepass.generatePassword,
     'get_connected_database': kpxcEvent.onGetConnectedDatabase,
diff --git a/keepassxc-browser/background/httpauth.js b/keepassxc-browser/background/httpauth.js
index 5457caa..cdd23ed 100755
--- a/keepassxc-browser/background/httpauth.js
+++ b/keepassxc-browser/background/httpauth.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const httpAuth = {};
 
 httpAuth.requests = [];
diff --git a/keepassxc-browser/background/init.js b/keepassxc-browser/background/init.js
index 4f6c6af..ce7fed7 100644
--- a/keepassxc-browser/background/init.js
+++ b/keepassxc-browser/background/init.js
@@ -1,3 +1,5 @@
+'use strict';
+
 keepass.migrateKeyRing().then(() => {
     page.initSettings().then(() => {
         page.initOpenedTabs().then(() => {
diff --git a/keepassxc-browser/background/keepass.js b/keepassxc-browser/background/keepass.js
index d7edd2f..6dec6aa 100755
--- a/keepassxc-browser/background/keepass.js
+++ b/keepassxc-browser/background/keepass.js
@@ -18,6 +18,7 @@ keepass.keySize = 24;
 keepass.latestVersionUrl = 'https://api.github.com/repos/keepassxreboot/keepassxc/releases/latest';
 keepass.cacheTimeout = 30 * 1000; // milliseconds
 keepass.databaseHash = 'no-hash'; //no-hash = KeePassXC is too old and does not return a hash value
+keepass.previousDatabaseHash = 'no-hash';
 keepass.keyId = 'keepassxc-browser-cryptokey-name';
 keepass.keyBody = 'keepassxc-browser-key';
 keepass.messageTimeout = 500; // milliseconds
@@ -835,11 +836,22 @@ keepass.onNativeMessage = function(response) {
 
     // Handle database lock/unlock status
     if (response.action === kpActions.DATABASE_LOCKED || response.action === kpActions.DATABASE_UNLOCKED) {
-        keepass.testAssociation((response) => {
+        keepass.testAssociation((associationResponse) => {
             keepass.isConfigured().then((configured) => {
                 let data = page.tabs[page.currentTabId].stack[page.tabs[page.currentTabId].stack.length - 1];
                 data.iconType = configured ? 'normal' : 'cross';
                 browserAction.show(null, {'id': page.currentTabId});
+
+                // Send message to content script
+                browser.tabs.query({ active: true, currentWindow: true }).then((tabs) => {
+                    if (tabs.length) {
+                        browser.tabs.sendMessage(tabs[0].id, {
+                            action: 'check_database_hash',
+                            hash: {old: kpxcEvent.previousDatabaseHash, new: keepass.databaseHash}
+                        });
+                        keepass.previousDatabaseHash = keepass.databaseHash;
+                    }
+                });
             });
         }, null);
     }
diff --git a/keepassxc-browser/background/page.js b/keepassxc-browser/background/page.js
index 2d6a2d1..60be892 100755
--- a/keepassxc-browser/background/page.js
+++ b/keepassxc-browser/background/page.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const defaultSettings = {
     checkUpdateKeePassXC: 3,
     autoCompleteUsernames: true,
@@ -11,9 +13,9 @@ const defaultSettings = {
 };
 
 var page = {};
-page.tabs = {};
+page.tabs = [];
 page.currentTabId = -1;
-page.blockedTabs = {};
+page.blockedTabs = [];
 
 page.initSettings = function() {
     return new Promise((resolve, reject) => {
@@ -109,7 +111,7 @@ page.createTabEntry = function(tabId) {
     page.tabs[tabId] = {
         'stack': [],
         'errorMessage': null,
-        'loginList': {}
+        'loginList': []
     };
 };
 
diff --git a/keepassxc-browser/global.js b/keepassxc-browser/global.js
index 558dc9d..55456cd 100755
--- a/keepassxc-browser/global.js
+++ b/keepassxc-browser/global.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var isFirefox = function() {
     if (!(/Chrome/.test(navigator.userAgent) && /Google/.test(navigator.vendor))) {
         return true;
diff --git a/keepassxc-browser/keepassxc-browser.js b/keepassxc-browser/keepassxc-browser.js
index c9561b8..dab0c74 100755
--- a/keepassxc-browser/keepassxc-browser.js
+++ b/keepassxc-browser/keepassxc-browser.js
@@ -1,3 +1,5 @@
+'use strict';
+
 // contains already called method names
 var _called = {};
 _called.retrieveCredentials = false;
@@ -73,6 +75,9 @@ browser.runtime.onMessage.addListener(function(req, sender, callback) {
                 cip.initCredentialFields(true);
             });
         }
+        else if (req.action === 'check_database_hash' && 'hash' in req) {
+            cip.detectDatabaseChange(req.hash);
+        }
     }
 });
 
@@ -814,7 +819,7 @@ cipFields.prepareId = function(id) {
 // Check aria-hidden attribute by looping the parent elements of input field
 cipFields.getAriaHidden = function(field) {
     let $par = jQuery(field).parents();
-    for (p of $par) {
+    for (const p of $par) {
         const val = $(p).attr('aria-hidden');
         if (val) {
             return val;
@@ -825,7 +830,7 @@ cipFields.getAriaHidden = function(field) {
 
 cipFields.getOverflowHidden = function(field) {
     let $par = jQuery(field).parents();
-    for (p of $par) {
+    for (const p of $par) {
         const val = $(p).css('overflow');
         if (val === 'hidden') {
             return true;
@@ -1155,7 +1160,6 @@ cip.credentials = [];
 jQuery(function() {
     cip.init();
     cip.detectNewActiveFields();
-    cip.detectDatabaseChange();
 });
 
 cip.init = function() {
@@ -1182,46 +1186,36 @@ cip.detectNewActiveFields = function() {
 };
 
 // Switch credentials if database is changed or closed
-cip.detectDatabaseChange = function() {
-    let dbDetectInterval = setInterval(function() {
-        if (document.visibilityState !== 'hidden') {
+cip.detectDatabaseChange = function(response) {
+    if (document.visibilityState !== 'hidden') {
+        if (response.new === 'no-hash' && response.old !== 'no-hash') {
+            cipEvents.clearCredentials();
+
             browser.runtime.sendMessage({
-                action: 'check_databasehash'
+                action: 'page_clear_logins'
+            });
+
+            // Switch back to default popup
+            browser.runtime.sendMessage({
+                action: 'get_status',
+                args: [ true ]    // Set polling to true, this is an internal function call
+            });
+        } else if (response.new !== 'no-hash' && response.new !== response.old) {
+            browser.runtime.sendMessage({
+                action: 'load_settings',
             }).then((response) => {
-                if (response.new === 'no-hash' && response.old !== 'no-hash') {
-                    cipEvents.clearCredentials();
+                cip.settings = response;
+                cip.initCredentialFields(true);
 
-                    browser.runtime.sendMessage({
-                        action: 'page_clear_logins'
-                    });
-
-                    // Switch back to default popup
-                    browser.runtime.sendMessage({
-                        action: 'get_status',
-                        args: [ true ]    // Set polling to true, this is an internal function call
-                    });
-                } else {
-                    if (response.new !== 'no-hash' && response.new !== response.old) {
-                        browser.runtime.sendMessage({
-                            action: 'load_settings',
-                        }).then((response) => {
-                            cip.settings = response;
-                            cip.initCredentialFields(true);
-
-                            // If user has requested a manual fill through context menu the actual credential filling
-                            // is handled here when the opened database has been regognized. It's not a pretty hack.
-                            if (_called.manualFillRequested && _called.manualFillRequested !== 'none') {
-                                cip.fillInFromActiveElement(false, (_called.manualFillRequested === 'pass' ? true : false));
-                                _called.manualFillRequested = 'none';
-                            }
-                        });
-                    }
+                // If user has requested a manual fill through context menu the actual credential filling
+                // is handled here when the opened database has been regognized. It's not a pretty hack.
+                if (_called.manualFillRequested && _called.manualFillRequested !== 'none') {
+                    cip.fillInFromActiveElement(false, _called.manualFillRequested === 'pass');
+                    _called.manualFillRequested = 'none';
                 }
-            }).catch((e) => {
-                console.log(e);
             });
         }
-    }, 1000);
+    }
 };
 
 cip.initCredentialFields = function(forceCall) {
diff --git a/keepassxc-browser/options/options.js b/keepassxc-browser/options/options.js
index e7db3aa..2b5cad3 100644
--- a/keepassxc-browser/options/options.js
+++ b/keepassxc-browser/options/options.js
@@ -1,3 +1,5 @@
+'use strict';
+
 if (jQuery) {
     var $ = jQuery.noConflict(true);
 }
diff --git a/keepassxc-browser/popups/popup.js b/keepassxc-browser/popups/popup.js
index be96e5c..98511aa 100644
--- a/keepassxc-browser/popups/popup.js
+++ b/keepassxc-browser/popups/popup.js
@@ -1,3 +1,5 @@
+'use strict';
+
 function status_response(r) {
     $('#initial-state').hide();
     $('#error-encountered').hide();
diff --git a/keepassxc-browser/popups/popup_functions.js b/keepassxc-browser/popups/popup_functions.js
index 1eee4ac..83bd82d 100644
--- a/keepassxc-browser/popups/popup_functions.js
+++ b/keepassxc-browser/popups/popup_functions.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var $ = jQuery.noConflict(true);
 
 function updateAvailableResponse(available) {
diff --git a/keepassxc-browser/popups/popup_httpauth.js b/keepassxc-browser/popups/popup_httpauth.js
index 9ce9271..cd68d91 100644
--- a/keepassxc-browser/popups/popup_httpauth.js
+++ b/keepassxc-browser/popups/popup_httpauth.js
@@ -1,3 +1,5 @@
+'use strict';
+
 $(function() {
     browser.runtime.getBackgroundPage().then((global) => {
         browser.tabs.query({'active': true, 'currentWindow': true}).then((tabs) => {
diff --git a/keepassxc-browser/popups/popup_login.js b/keepassxc-browser/popups/popup_login.js
index eae62d3..b0c2f74 100644
--- a/keepassxc-browser/popups/popup_login.js
+++ b/keepassxc-browser/popups/popup_login.js
@@ -1,3 +1,5 @@
+'use strict';
+
 $(function() {
     browser.runtime.getBackgroundPage().then((global) => {
         browser.tabs.query({'active': true, 'currentWindow': true}).then((tabs) => {
diff --git a/keepassxc-browser/popups/popup_remember.js b/keepassxc-browser/popups/popup_remember.js
index be79328..c8de9f1 100644
--- a/keepassxc-browser/popups/popup_remember.js
+++ b/keepassxc-browser/popups/popup_remember.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var _tab;
 
 function _initialize(tab) {