Index: js/global.js
===================================================================
--- js/global.js
+++ js/global.js
@@ -262,6 +262,18 @@
 window.addEventListener('load', adjust_scroll_onload, { once: true });
 window.addEventListener('hashchange', adjust_scroll_onload);
 
+// Focus the quicksearch field in the header when ALT+s (or OPT+s on macOS) is
+// pressed.
+window.addEventListener('keydown', (event) => {
+    if (event.altKey && String.fromCharCode(event.which) === 'S') {
+        const qsElement = document.querySelector('#quicksearch_top');
+        if (qsElement) {
+            event.preventDefault();
+            qsElement.focus();
+        }
+    }
+});
+
 window.addEventListener('DOMContentLoaded', () => {
   const announcement = document.getElementById('new_announcement');
   if (announcement) {
Index: template/en/default/global/header.html.tmpl
===================================================================
--- template/en/default/global/header.html.tmpl
+++ template/en/default/global/header.html.tmpl
@@ -271,7 +271,7 @@
         <input role="searchbox" id="quicksearch_top" class="dropdown-button" name="quicksearch" autocomplete="off"
                value="[% quicksearch FILTER html %]" placeholder="Search [% terms.Bugs %]"
                title="Enter a [% terms.bug %] number or some search terms" aria-controls="header-search-dropdown"
-               accesskey="s" aria-label="Quick Search">
+               aria-label="Quick Search">
         [% PROCESS "global/header-search-dropdown.html.tmpl" %]
       </section>
     </form>