diff --git a/background/background.js b/background/background.js
index 1bcef0db..c51a375b 100644
--- a/background/background.js
+++ b/background/background.js
@@ -178,7 +178,7 @@ browserCommands = {
     openURL({url: 'manage.html'});
   },
   openOptions() {
-    openURL({url: 'manage.html?#stylus-options'});
+    openURL({url: 'manage.html#stylus-options'});
   },
   styleDisableAll(info) {
     prefs.set('disableAll', info ? info.checked : !prefs.get('disableAll'));
diff --git a/js/messaging.js b/js/messaging.js
index d809d1bb..d6652777 100644
--- a/js/messaging.js
+++ b/js/messaging.js
@@ -1,6 +1,7 @@
 /* exported getActiveTab onTabReady stringAsRegExp getTabRealURL openURL
   getStyleWithNoCode tryRegExp sessionStorageHash download deepEqual
   closeCurrentTab capitalize */
+/* global prefs */
 'use strict';
 
 const CHROME = Boolean(chrome.app) && parseInt(navigator.userAgent.match(/Chrom\w+\/(?:\d+\.){2}(\d+)|$/)[1]);
@@ -225,7 +226,7 @@ function openURL({
   url = url.replace(/^(opera|vivaldi)/, 'chrome');
   const editMatch = /edit\.html/.test(url);
   // ignore filtered manager URLs with params & edit URLs created from popup on manager page
-  const manageMatch = !editMatch ? /manage\.html(\?#stylus-options)?$/.test(url) : null;
+  const manageMatch = !editMatch ? /manage\.html(#stylus-options)?$/.test(url) : null;
   // FF doesn't handle moz-extension:// URLs (bug)
   // FF decodes %2F in encoded parameters (bug)
   // API doesn't handle the hash-fragment part
@@ -243,9 +244,10 @@ function openURL({
   function maybeSwitch(tabs = []) {
     const urlWithSlash = url + '/';
     const urlFF = FIREFOX && url.replace(/%2F/g, '/');
-    const urlOptions = manageMatch ? URLS.ownOrigin + 'manage.html?#stylus-options' : null;
+    const urlOptions = manageMatch ? URLS.ownOrigin + 'manage.html#stylus-options' : null;
     const urlManage = manageMatch ? URLS.ownOrigin + 'manage.html' : null;
-    let tab = tabs.find(({url: u}) => u === url || u === urlFF || u === urlWithSlash || u === urlOptions || u === urlManage);
+    const tab = tabs.find(({url: u}) => u === url || u === urlFF || u === urlWithSlash ||
+                          u === urlOptions || u === urlManage);
     if (!tab && prefs.get('openEditInWindow') && chrome.windows && editMatch) {
       chrome.windows.create(
         Object.assign({
@@ -264,8 +266,7 @@ function openURL({
       }
       getActiveTab()
         .then(currentTab => {
-          const closePopup = tab && FIREFOX && currentTab.windowId !== tab.windowId ? false : true;
-          if (closePopup) {
+          if (!(tab && FIREFOX && currentTab.windowId !== tab.windowId)) {
             chrome.runtime.sendMessage({
               'name': 'popup',
               'data': 'close-popup'
diff --git a/manage/import-export.js b/manage/import-export.js
index 327314c0..3815de8d 100644
--- a/manage/import-export.js
+++ b/manage/import-export.js
@@ -7,8 +7,12 @@ const STYLISH_DUMP_FILE_EXT = '.txt';
 const STYLUS_BACKUP_FILE_EXT = '.json';
 
 onDOMready().then(() => {
-  $('#file-all-styles').onclick = exportToFile;
-  $('#unfile-all-styles').onclick = () => {
+  $('#file-all-styles').onclick = event => {
+    event.preventDefault();
+    exportToFile();
+  };
+  $('#unfile-all-styles').onclick = event => {
+    event.preventDefault();
     importFromFile({fileTypeFilter: STYLUS_BACKUP_FILE_EXT});
   };
 
diff --git a/manage/manage.js b/manage/manage.js
index 83221f16..ed9ff34c 100644
--- a/manage/manage.js
+++ b/manage/manage.js
@@ -84,7 +84,8 @@ function onRuntimeMessage(msg) {
 function initGlobalEvents() {
   installed = $('#installed');
   installed.onclick = handleEvent.entryClicked;
-  $('#manage-options-button').onclick = () => history.replaceState('', document.title, location.href + '?#stylus-options');
+  $('#manage-options-button').onclick = () =>
+  history.replaceState('', document.title, location.href + '#stylus-options');
   {
     const btn = $('#manage-shortcuts-button');
     btn.onclick = btn.onclick || (() => openURL({url: URLS.configureCommands}));
@@ -719,7 +720,7 @@ function embedOptions() {
 
 function removeOptions() {
   const options = $('#stylus-embedded-options');
-  if (options) options.remove()
+  if (options) options.remove();
 }
 
 // wait for possible filter params to be removed
@@ -746,11 +747,11 @@ onDOMready().then(() => {
 
 function toggleOptions(msg) {
   if (msg === 'options-open' && location.hash !== '#stylus-options') {
-    history.replaceState('', document.title, location.href + '?#stylus-options');
+    history.replaceState('', document.title, location.href + '#stylus-options');
   } else if (msg === 'options-close' && location.hash === '#stylus-options') {
     history.replaceState('', document.title, location.origin + location.pathname);
   }
-};
+}
 
 
 if (location.hash === '#stylus-options') embedOptions();
diff --git a/options/options.js b/options/options.js
index e8a5d2de..6feb02c4 100644
--- a/options/options.js
+++ b/options/options.js
@@ -40,8 +40,8 @@ if (FIREFOX && 'update' in (chrome.commands || {})) {
 
 // actions
 $('#options-close-icon').onclick = () => {
-  window.top.history.replaceState('', window.top.document.title, window.top.location.origin + window.top.location.pathname);
-}
+  top.history.replaceState('', top.document.title, top.location.origin + top.location.pathname);
+};
 
 document.onclick = e => {
   const target = e.target.closest('[data-cmd]');
@@ -299,9 +299,9 @@ function customizeHotkeys() {
 
 window.onkeydown = event => {
   if (event.keyCode === 27) {
-    window.top.history.replaceState('', window.top.document.title, window.top.location.origin + window.top.location.pathname);
+    top.history.replaceState('', top.document.title, top.location.origin + top.location.pathname);
   }
-}
+};
 
 // FF is slow to allow focus, particularly when launched via manager button
 setTimeout(() => {
diff --git a/popup/popup.js b/popup/popup.js
index f328ff6c..85622269 100644
--- a/popup/popup.js
+++ b/popup/popup.js
@@ -106,7 +106,7 @@ function initPopup() {
   });
 
   $('#popup-options-button').onclick = () => {
-    API.openURL({url: 'manage.html?#stylus-options'});
+    API.openURL({url: 'manage.html#stylus-options'});
     window.close();
   };
 
diff --git a/sync/import-export-dropbox.js b/sync/import-export-dropbox.js
index 222df852..f72c711a 100644
--- a/sync/import-export-dropbox.js
+++ b/sync/import-export-dropbox.js
@@ -48,7 +48,8 @@ function uploadFileDropbox(client, stylesText) {
   return client.filesUpload({path: '/' + DROPBOX_FILE, contents: stylesText});
 }
 
-$('#sync-dropbox-export').onclick = () => {
+$('#sync-dropbox-export').onclick = event => {
+  event.preventDefault();
   const mode = localStorage.installType;
   const title = t('syncDropboxStyles');
   const text = mode === 'normal' ? t('connectingDropbox') : t('connectingDropboxNotAllowed');
@@ -122,7 +123,8 @@ $('#sync-dropbox-export').onclick = () => {
   });
 };
 
-$('#sync-dropbox-import').onclick = () => {
+$('#sync-dropbox-import').onclick = event => {
+  event.preventDefault();
   const mode = localStorage.installType;
   const title = t('retrieveDropboxSync');
   const text = mode === 'normal' ? t('connectingDropbox') : t('connectingDropboxNotAllowed');