diff --git a/public/javascripts/signup.js b/public/javascripts/signup.js
index 7476130c15..d517e21d8e 100644
--- a/public/javascripts/signup.js
+++ b/public/javascripts/signup.js
@@ -2,7 +2,7 @@ $(function() {
   const $form = $('#signup_form');
   const $exists = $form.find('.username-exists');
 
-  const usernameCheck = lichess.debounce(function() {
+  const usernameCheck = lichess.debounce(() => {
     const name = $username.val();
     if (name.length >= 3) $.ajax({
       method: 'GET',
@@ -11,27 +11,27 @@ $(function() {
         term: name,
         exists: 1
       },
-      success: function(res) {
+      success(res) {
         $exists.toggle(res);
       }
     });
   }, 300);
 
   $username = $form.find('input[name="username"]')
-    .on('change keyup paste', function() {
+    .on('change keyup paste', () => {
       $exists.hide();
       usernameCheck();
     });
 
-  $form.on('submit', function() {
+  $form.on('submit', () =>
     $form.find('button.submit')
-      .attr('disabled', true)
-      .removeAttr('data-icon')
-      .addClass('frameless')
-      .html(lichess.spinnerHtml);
-  });
+    .attr('disabled', true)
+    .removeAttr('data-icon')
+    .addClass('frameless')
+    .html(lichess.spinnerHtml)
+  );
 });
-window.signupSubmit = function(token) {
+window.signupSubmit = () => {
   const form = document.getElementById('signup_form');
   if (form.reportValidity()) form.submit();
 }
diff --git a/ui/site/src/main.js b/ui/site/src/main.js
index d121689b86..6b9a6f667e 100644
--- a/ui/site/src/main.js
+++ b/ui/site/src/main.js
@@ -129,7 +129,7 @@
       }, {
         hint: true,
         highlight: false,
-        source: function(query, _, runAsync) {
+        source(query, _, runAsync) {
           query = query.trim();
           if (!query.match(/^[a-z0-9][\w-]{2,29}$/i)) return;
           else if (cache[query]) setTimeout(() => runAsync(cache[query]), 50);
@@ -164,8 +164,8 @@
         templates: {
           empty: '<div class="empty">No player found</div>',
           pending: lichess.spinnerHtml,
-          suggestion: function(o) {
-            var tag = opts.tag || 'a';
+          suggestion(o) {
+            const tag = opts.tag || 'a';
             return '<' + tag + ' class="ulpt user-link' + (o.online ? ' online' : '') + '" ' + (tag === 'a' ? '' : 'data-') + 'href="/@/' + o.name + '">' +
               '<i class="line' + (o.patron ? ' patron' : '') + '"></i>' + (o.title ? '<span class="utitle">' + o.title + '</span>&nbsp;' : '') + o.name +
               '</' + tag + '>';