diff --git a/qutebrowser/utils/javascript.py b/qutebrowser/utils/javascript.py
index 19e6b22c2..731af3ed6 100644
--- a/qutebrowser/utils/javascript.py
+++ b/qutebrowser/utils/javascript.py
@@ -54,7 +54,7 @@ def _convert_js_arg(arg):
     if arg is None:
         return 'undefined'
     elif isinstance(arg, str):
-        return string_escape(arg)
+        return '"{}"'.format(string_escape(arg))
     elif isinstance(arg, int):
         return str(arg)
     else:
diff --git a/tests/unit/utils/test_javascript.py b/tests/unit/utils/test_javascript.py
index 3cf649f6d..c2af199a1 100644
--- a/tests/unit/utils/test_javascript.py
+++ b/tests/unit/utils/test_javascript.py
@@ -123,8 +123,8 @@ class TestStringEscape:
 
 
 @pytest.mark.parametrize('arg, expected', [
-    ('foobar', 'foobar'),
-    ('foo\\bar', r'foo\\bar'),
+    ('foobar', '"foobar"'),
+    ('foo\\bar', r'"foo\\bar"'),
     (42, '42'),
     (None, 'undefined'),
     (object(), TypeError),