2 files changed, 15 insertions, 2 deletions
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 1fda0761c66..be57cf45ae4 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -105,7 +105,7 @@ use string_cache::{Atom, QualName};
 use style::restyle_hints::ElementSnapshot;
 use style::stylesheets::Stylesheet;
 use time;
-use url::Url;
+use url::{Host, Url};
 use util::str::{DOMString, split_html_space_chars, str_join};
 
 #[derive(JSTraceable, PartialEq, HeapSizeOf)]
@@ -1647,6 +1647,19 @@ impl DocumentMethods for Document {
         }
     }
 
+    // https://html.spec.whatwg.org/multipage/#relaxing-the-same-origin-restriction
+    fn Domain(&self) -> DOMString {
+        // TODO: This should use the effective script origin when it exists
+        let origin = self.window.get_url();
+
+        if let Some(&Host::Ipv6(ipv6)) = origin.host() {
+            // Omit square brackets for IPv6 addresses.
+            return DOMString::from(ipv6.serialize());
+        }
+
+        DOMString::from(origin.serialize_host().unwrap_or_else(|| "".to_owned()))
+    }
+
     // https://dom.spec.whatwg.org/#dom-document-documenturi
     fn DocumentURI(&self) -> DOMString {
         self.URL()
diff --git a/components/script/dom/webidls/Document.webidl b/components/script/dom/webidls/Document.webidl
index 5ccd72d087d..328c54b1c2e 100644
--- a/components/script/dom/webidls/Document.webidl
+++ b/components/script/dom/webidls/Document.webidl
@@ -81,7 +81,7 @@ partial /*sealed*/ interface Document {
   // resource metadata management
   // [PutForwards=href, Unforgeable]
   readonly attribute Location/*?*/ location;
-  // attribute DOMString domain;
+  readonly attribute DOMString domain;
   // readonly attribute DOMString referrer;
   [Throws]
   attribute DOMString cookie;