I would suggest doing something like this:

```diff
diff --git a/media/js/impala/search.js b/media/js/impala/search.js
index 8c631f4..ae16983 100644
--- a/media/js/impala/search.js
+++ b/media/js/impala/search.js
@@ -1,3 +1,7 @@
+(function() {
+
+var storage = z.Storage('search');
+
 function autofillPlatform(context) {
     var $context = $(context || document.body);
     $('#search', $context).bind('autofill', function(e) {
@@ -14,12 +18,26 @@ function autofillPlatform(context) {
             platform = '',
             appver_defined = typeof gv.appver !== 'undefined',
             platform_defined = typeof gv.platform !== 'undefined';
+
+        var appver_saved = storage.get('appver');
+        var platform_saved = storage.get('platform');
+
         if (appver_defined) {
             appver = gv.appver;
+            storage.set('appver', appver);
+        } else if (appver_saved !== null) {
+            appver_defined = true;
+            appver = appver_saved;
         }
+
         if (platform_defined) {
-            platform = gv.platform;
+            platform = gv.platform || platform_saved;
+            storage.set('platform', platform);
+        } else if (platform_saved !== null) {
+            platform_defined = true;
+            platform = platform_saved;
         }
+
         if (z.appMatchesUserAgent) {
             if (!appver_defined) {
                 appver = z.browserVersion;
@@ -170,3 +188,5 @@ $.fn.initSearchPjax = function($filters) {
     $container.bind('start.pjax', loading).bind('end.pjax', finished);
     $(document).keyup(_.throttle(turnPages, 300));
 };
+
+})();
```