Allow sending empty hidden values in eww

* lisp/net/eww.el (eww-tag-input): Allow sending empty hidden
values (bug#22388).

Copyright-paperwork-exempt: Yes
(cherry picked from commit 5898da8210af7953e638ddf7821c05260979c3f0)

Backport:

diff --git a/lisp/net/eww.el b/lisp/net/eww.el
index a96241d69f961ce5e5d0e5ad90c0e8b1c3e75847..5e24d4fef4edddf2b0697d1f763c67857346af6f 100644 (file)
--- a/lisp/net/eww.el
+++ b/lisp/net/eww.el
@@ -1132,7 +1132,7 @@ See URL `https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Input'.")
          (nconc eww-form (list
                           (list 'hidden
                                 :name name
-                                :value (dom-attr dom 'value)))))))
+                                :value (or (dom-attr dom 'value) "")))))))
      (t
       (eww-form-text dom)))
     (unless (= start (point))