diff --git a/qutebrowser/browser/webengine/webenginetab.py b/qutebrowser/browser/webengine/webenginetab.py
index ea646cda3..128b4c945 100644
--- a/qutebrowser/browser/webengine/webenginetab.py
+++ b/qutebrowser/browser/webengine/webenginetab.py
@@ -21,7 +21,7 @@
 
 import math
 import functools
-import platform
+import sys
 import html as html_utils
 
 import sip
@@ -206,8 +206,8 @@ class WebEngineCaret(browsertab.AbstractCaret):
             return
 
         self._tab.run_js_async(
-            javascript.assemble('caret', 'setInitialCursor',
-                                platform.platform()))
+            javascript.assemble('caret', 'setPlatform', sys.platform))
+        self._js_call('setInitialCursor')
 
     @pyqtSlot(usertypes.KeyMode)
     def _on_mode_left(self):
diff --git a/qutebrowser/javascript/webengine_caret.js b/qutebrowser/javascript/webengine_caret.js
index 052d3a4c1..7dafd9136 100644
--- a/qutebrowser/javascript/webengine_caret.js
+++ b/qutebrowser/javascript/webengine_caret.js
@@ -707,6 +707,12 @@ window._qutebrowser.caret = (function() {
      */
     CaretBrowsing.blinkFlag = true;
 
+    /**
+     * The os that user is using.
+     * @type {boolean}
+     */
+    CaretBrowsing.platform = null;
+
     /**
      * Check if a node is a control that normally allows the user to interact
      * with it using arrow keys. We won't override the arrow keys when such a
@@ -814,9 +820,9 @@ window._qutebrowser.caret = (function() {
      * If there's no initial selection, set the cursor just before the
      * first text character in the document.
      */
-    CaretBrowsing.setInitialCursor = function(platform) {
-        if (platform) {
-            CaretBrowsing.isWindows = platform.indexOf("Windows") !== -1;
+    CaretBrowsing.setInitialCursor = function() {
+        if (CaretBrowsing.platform) {
+            CaretBrowsing.isWindows = CaretBrowsing.platform.startsWith("win");
         }
         const selectionRange = window.getSelection().toString().length;
         if (selectionRange === 0) {
@@ -1252,7 +1258,7 @@ window._qutebrowser.caret = (function() {
         CaretBrowsing.isCaretVisible =
             (CaretBrowsing.isEnabled && CaretBrowsing.isWindowFocused);
         if (CaretBrowsing.isCaretVisible && !CaretBrowsing.caretElement) {
-            CaretBrowsing.setInitialCursor(CaretBrowsing.isWindows);
+            CaretBrowsing.setInitialCursor();
             CaretBrowsing.updateCaretOrSelection(true);
             if (CaretBrowsing.caretElement) {
                 CaretBrowsing.blinkFunctionId = window.setInterval(
@@ -1304,9 +1310,9 @@ window._qutebrowser.caret = (function() {
 
     const funcs = {};
 
-    funcs.setInitialCursor = (platform) => {
+    funcs.setInitialCursor = () => {
         if (!CaretBrowsing.initiated) {
-            CaretBrowsing.setInitialCursor(platform);
+            CaretBrowsing.setInitialCursor();
             return;
         }
 
@@ -1316,6 +1322,10 @@ window._qutebrowser.caret = (function() {
         CaretBrowsing.toggle();
     };
 
+    funcs.setPlatform = (platform) => {
+        CaretBrowsing.platform = platform;
+    }
+
     funcs.disableCaret = () => {
         CaretBrowsing.toggle(false);
     };