diff --git a/js/feedlist.js b/js/feedlist.js
index 8c5cb73e0..10be5126b 100644
--- a/js/feedlist.js
+++ b/js/feedlist.js
@@ -1,12 +1,12 @@
-var _infscroll_disable = 0;
-var _infscroll_request_sent = 0;
+let _infscroll_disable = 0;
+let _infscroll_request_sent = 0;
 
-var _search_query = false;
-var _viewfeed_last = 0;
-var _viewfeed_timeout = false;
+let _search_query = false;
+let _viewfeed_last = 0;
+let _viewfeed_timeout = false;
 
-var counters_last_request = 0;
-var _counters_prev = [];
+let counters_last_request = 0;
+let _counters_prev = [];
 
 function resetCounterCache() {
 	_counters_prev = [];
diff --git a/js/prefs.js b/js/prefs.js
index e67d80df4..cfc2d6c52 100755
--- a/js/prefs.js
+++ b/js/prefs.js
@@ -1,9 +1,9 @@
-var init_params = new Array();
+let init_params = new Array();
 
-var hotkey_prefix = false;
-var hotkey_prefix_pressed = false;
+let hotkey_prefix = false;
+let hotkey_prefix_pressed = false;
 
-var seq = "";
+let seq = "";
 
 function notify_callback2(transport, sticky) {
 	notify_info(transport.responseText, sticky);
diff --git a/js/tt-rss.js b/js/tt-rss.js
index 872407e73..b2b6da3c0 100644
--- a/js/tt-rss.js
+++ b/js/tt-rss.js
@@ -1,11 +1,11 @@
-var global_unread = -1;
-var hotkey_prefix = false;
-var hotkey_prefix_pressed = false;
-var hotkey_actions = {};
-var _widescreen_mode = false;
-var _rpc_seq = 0;
-var _active_feed_id = 0;
-var _active_feed_is_cat = false;
+let global_unread = -1;
+let hotkey_prefix = false;
+let hotkey_prefix_pressed = false;
+let hotkey_actions = {};
+let _widescreen_mode = false;
+let _rpc_seq = 0;
+let _active_feed_id = 0;
+let _active_feed_is_cat = false;
 
 function next_seq() {
 	_rpc_seq += 1;
diff --git a/js/viewfeed.js b/js/viewfeed.js
index 8f1605fac..e23c357ff 100755
--- a/js/viewfeed.js
+++ b/js/viewfeed.js
@@ -1,23 +1,23 @@
-var _active_article_id = 0;
+let _active_article_id = 0;
 
-var vgroup_last_feed = false;
-var post_under_pointer = false;
+let vgroup_last_feed = false;
+let post_under_pointer = false;
 
-var last_requested_article = false;
+let last_requested_article = false;
 
-var catchup_id_batch = [];
-var catchup_timeout_id = false;
+let catchup_id_batch = [];
+let catchup_timeout_id = false;
 
-var cids_requested = [];
-var loaded_article_ids = [];
-var _last_headlines_update = 0;
-var _headlines_scroll_offset = 0;
-var current_first_id = 0;
-var last_search_query;
+let cids_requested = [];
+let loaded_article_ids = [];
+let _last_headlines_update = 0;
+let _headlines_scroll_offset = 0;
+let current_first_id = 0;
+let last_search_query;
 
-var _catchup_request_sent = false;
+let _catchup_request_sent = false;
 
-var has_storage = 'sessionStorage' in window && window['sessionStorage'] !== null;
+let has_storage = 'sessionStorage' in window && window['sessionStorage'] !== null;
 
 function headlines_callback2(transport, offset, background, infscroll_req) {
 	handle_rpc_json(transport);