3 files changed, 19 insertions, 4 deletions
diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index a8461618db9..3ac799fdc04 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -410,7 +410,7 @@ impl<'a> FormSubmitter<'a> {
     }
 }
 
-pub trait FormOwner<'a> : Copy {
+pub trait FormControl<'a> : Copy {
     fn form_owner(self) -> Option<Temporary<HTMLFormElement>>;
     fn get_form_attribute(self,
                           attr: &Atom,
@@ -423,4 +423,6 @@ pub trait FormOwner<'a> : Copy {
         }
     }
     fn to_element(self) -> JSRef<'a, Element>;
+    // https://html.spec.whatwg.org/multipage/forms.html#concept-fe-mutable
+    fn mutable(self) -> bool;
 }
diff --git a/components/script/dom/htmlinputelement.rs b/components/script/dom/htmlinputelement.rs
index 378952d4da3..30b4dcaa820 100644
--- a/components/script/dom/htmlinputelement.rs
+++ b/components/script/dom/htmlinputelement.rs
@@ -23,7 +23,7 @@ use dom::event::Event;
 use dom::eventtarget::{EventTarget, NodeTargetTypeId};
 use dom::htmlelement::HTMLElement;
 use dom::keyboardevent::KeyboardEvent;
-use dom::htmlformelement::{InputElement, FormOwner, HTMLFormElement, HTMLFormElementHelpers, NotFromFormSubmitMethod};
+use dom::htmlformelement::{InputElement, FormControl, HTMLFormElement, HTMLFormElementHelpers, NotFromFormSubmitMethod};
 use dom::node::{DisabledStateHelpers, Node, NodeHelpers, ElementNodeTypeId, document_from_node, window_from_node};
 use dom::virtualmethods::VirtualMethods;
 use textinput::{Single, TextInput, TriggerDefaultAction, DispatchInput, Nothing};
@@ -151,6 +151,12 @@ impl<'a> HTMLInputElementMethods for JSRef<'a, HTMLInputElement> {
     // https://html.spec.whatwg.org/multipage/forms.html#dom-input-checked
     make_bool_setter!(SetChecked, "checked")
 
+    // https://html.spec.whatwg.org/multipage/forms.html#dom-input-readonly
+    make_bool_getter!(ReadOnly)
+
+    // https://html.spec.whatwg.org/multipage/forms.html#dom-input-readonly
+    make_bool_setter!(SetReadOnly, "readonly")
+
     // https://html.spec.whatwg.org/multipage/forms.html#dom-input-size
     make_uint_getter!(Size)
 
@@ -457,7 +463,7 @@ impl Reflectable for HTMLInputElement {
     }
 }
 
-impl<'a> FormOwner<'a> for JSRef<'a, HTMLInputElement> {
+impl<'a> FormControl<'a> for JSRef<'a, HTMLInputElement> {
     // FIXME: This is wrong (https://github.com/servo/servo/issues/3553)
     //        but we need html5ever to do it correctly
     fn form_owner(self) -> Option<Temporary<HTMLFormElement>> {
@@ -485,4 +491,11 @@ impl<'a> FormOwner<'a> for JSRef<'a, HTMLInputElement> {
     fn to_element(self) -> JSRef<'a, Element> {
         ElementCast::from_ref(self)
     }
+
+    // https://html.spec.whatwg.org/multipage/forms.html#concept-fe-mutable
+    fn mutable(self) -> bool {
+        // https://html.spec.whatwg.org/multipage/forms.html#the-input-element:concept-fe-mutable
+        // https://html.spec.whatwg.org/multipage/forms.html#the-readonly-attribute:concept-fe-mutable
+        !(self.Disabled() || self.ReadOnly())
+    }
 }
diff --git a/components/script/dom/webidls/HTMLInputElement.webidl b/components/script/dom/webidls/HTMLInputElement.webidl
index b69d8fcf4ff..32b4f04261b 100644
--- a/components/script/dom/webidls/HTMLInputElement.webidl
+++ b/components/script/dom/webidls/HTMLInputElement.webidl
@@ -32,7 +32,7 @@ interface HTMLInputElement : HTMLElement {
            attribute DOMString name;
   //         attribute DOMString pattern;
   //         attribute DOMString placeholder;
-  //         attribute boolean readOnly;
+           attribute boolean readOnly;
   //         attribute boolean required;
            attribute unsigned long size;
   //         attribute DOMString src;