3 files changed, 33 insertions, 1 deletions
diff --git a/components/script/dom/htmliframeelement.rs b/components/script/dom/htmliframeelement.rs
index e9e1fae2e27..59c7011a9c7 100644
--- a/components/script/dom/htmliframeelement.rs
+++ b/components/script/dom/htmliframeelement.rs
@@ -6,6 +6,7 @@ use dom::attr::Attr;
 use dom::attr::AttrHelpers;
 use dom::bindings::codegen::Bindings::HTMLIFrameElementBinding;
 use dom::bindings::codegen::Bindings::HTMLIFrameElementBinding::HTMLIFrameElementMethods;
+use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::InheritTypes::{NodeCast, ElementCast};
 use dom::bindings::codegen::InheritTypes::{HTMLElementCast, HTMLIFrameElementDerived};
 use dom::bindings::js::{JSRef, Temporary, OptionalRootable};
@@ -16,6 +17,7 @@ use dom::element::AttributeHandlers;
 use dom::eventtarget::{EventTarget, NodeTargetTypeId};
 use dom::htmlelement::HTMLElement;
 use dom::node::{Node, NodeHelpers, ElementNodeTypeId, window_from_node};
+use dom::urlhelper::UrlHelper;
 use dom::virtualmethods::VirtualMethods;
 use dom::window::Window;
 use page::IterablePage;
@@ -180,6 +182,22 @@ impl<'a> HTMLIFrameElementMethods for JSRef<'a, HTMLIFrameElement> {
             })
         })
     }
+
+    fn GetContentDocument(self) -> Option<Temporary<Document>> {
+        self.GetContentWindow().root().and_then(|window| {
+            let self_url = match self.get_url() {
+                Some(self_url) => self_url,
+                None => return None,
+            };
+            let win_url = window_from_node(self).root().page().get_url();
+
+            if UrlHelper::SameOrigin(&self_url, &win_url) {
+                Some(window.Document())
+            } else {
+                None
+            }
+        })
+    }
 }
 
 impl<'a> VirtualMethods for JSRef<'a, HTMLIFrameElement> {
diff --git a/components/script/dom/urlhelper.rs b/components/script/dom/urlhelper.rs
index f678e273876..251f8283e1e 100644
--- a/components/script/dom/urlhelper.rs
+++ b/components/script/dom/urlhelper.rs
@@ -27,4 +27,18 @@ impl UrlHelper {
             Some(ref hash) => format!("#{}", hash)
         }
     }
+
+    /// https://html.spec.whatwg.org/multipage/browsers.html#same-origin
+    pub fn SameOrigin(urlA: &Url, urlB: &Url) -> bool {
+        if urlA.host() != urlB.host() {
+            return false
+        }
+        if urlA.scheme != urlB.scheme {
+            return false
+        }
+        if urlA.port() != urlB.port() {
+            return false
+        }
+        return true
+    }
 }
diff --git a/components/script/dom/webidls/HTMLIFrameElement.webidl b/components/script/dom/webidls/HTMLIFrameElement.webidl
index 201f8700ce4..7768065545c 100644
--- a/components/script/dom/webidls/HTMLIFrameElement.webidl
+++ b/components/script/dom/webidls/HTMLIFrameElement.webidl
@@ -14,7 +14,7 @@ interface HTMLIFrameElement : HTMLElement {
   //         attribute boolean allowFullscreen;
   //         attribute DOMString width;
   //         attribute DOMString height;
-  //readonly attribute Document? contentDocument;
+  readonly attribute Document? contentDocument;
   //readonly attribute WindowProxy? contentWindow;
   readonly attribute Window? contentWindow;