From a45e1d9d95831077d3dcaf2cec696c43720a7bd5 Mon Sep 17 00:00:00 2001
From: Corey Farwell <coreyf@rwell.org>
Date: Thu, 13 Oct 2016 23:34:55 -0400
Subject: [PATCH] Implement "reset algorithm" for `<select>`.

---
 components/script/dom/htmlformelement.rs   |  3 +--
 components/script/dom/htmlselectelement.rs | 10 ++++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 090aa8553bf..26a30d07599 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -634,8 +634,7 @@ impl HTMLFormElement {
                 //    {}
                 //}
                 NodeTypeId::Element(ElementTypeId::HTMLElement(HTMLElementTypeId::HTMLSelectElement)) => {
-                    // Unimplemented
-                    {}
+                    child.downcast::<HTMLSelectElement>().unwrap().reset();
                 }
                 NodeTypeId::Element(ElementTypeId::HTMLElement(HTMLElementTypeId::HTMLTextAreaElement)) => {
                     child.downcast::<HTMLTextAreaElement>().unwrap().reset();
diff --git a/components/script/dom/htmlselectelement.rs b/components/script/dom/htmlselectelement.rs
index 34c9187b644..03d10e117f4 100644
--- a/components/script/dom/htmlselectelement.rs
+++ b/components/script/dom/htmlselectelement.rs
@@ -84,6 +84,16 @@ impl HTMLSelectElement {
                            HTMLSelectElementBinding::Wrap)
     }
 
+    // https://html.spec.whatwg.org/multipage/#the-select-element:concept-form-reset-control
+    pub fn reset(&self) {
+        let node = self.upcast::<Node>();
+        for opt in node.traverse_preorder().filter_map(Root::downcast::<HTMLOptionElement>) {
+            opt.set_selectedness(opt.DefaultSelected());
+            opt.set_dirtiness(false);
+        }
+        self.ask_for_reset();
+    }
+
     // https://html.spec.whatwg.org/multipage/#ask-for-a-reset
     pub fn ask_for_reset(&self) {
         if self.Multiple() {