Add new function dom-remove-attribute

* doc/lispref/text.texi (Document Object Model): Document it.

* lisp/dom.el (dom-remove-attribute): Add new function.

doc/lispref/text.texi

@@ -5161,6 +5161,9 @@ The following are functions for altering the @acronym{DOM}.
 @item dom-set-attribute @var{node} @var{attribute} @var{value}
 Set the @var{attribute} of the node to @var{value}.
 
+@item dom-remove-attribute @var{node} @var{attribute}
+Remove @var{attribute} from @var{node}.
+
 @item dom-append-child @var{node} @var{child}
 Append @var{child} as the last child of @var{node}.
 

etc/NEWS

@@ -358,6 +358,9 @@ optional argument specifying whether to follow symbolic links.
 ** 'parse-time-string' can now parse ISO 8601 format strings,
 such as "2020-01-15T16:12:21-08:00".
 
++++
+** The new function 'dom-remove-attribute' has been added.
+
 ---
 ** 'make-network-process', 'make-serial-process' :coding behavior change.
 Previously, passing ":coding nil" to either of these functions would

lisp/dom.el

@@ -67,6 +67,12 @@
 	(setcdr old value)
       (setcar (cdr node) (nconc (cadr node) (list (cons attribute value)))))))
 
+(defun dom-remove-attribute (node attribute)
+  "Remove ATTRIBUTE from NODE."
+  (setq node (dom-ensure-node node))
+  (when-let ((old (assoc attribute (cadr node))))
+    (setcar (cdr node) (delq old (cadr node)))))
+
 (defmacro dom-attr (node attr)
   "Return the attribute ATTR from NODE.
 A typical attribute is `href'."

test/lisp/dom-tests.el

@@ -84,6 +84,13 @@
     (dom-set-attribute dom attr value)
     (should (equal (dom-attr dom attr) value))))
 
+(ert-deftest dom-tests-remove-attribute ()
+  (let ((dom `(body ((foo . "bar") (zot . "foobar")))))
+    (should (equal (dom-attr dom 'foo) "bar"))
+    (dom-remove-attribute dom 'foo)
+    (should (equal (dom-attr dom 'foo) nil))
+    (should (equal dom '(body ((zot . "foobar")))))))
+
 (ert-deftest dom-tests-attr ()
   (let ((dom (dom-tests--tree)))
     (should-not (dom-attr dom 'id))