4 files changed, 17 insertions, 1 deletions
diff --git a/components/script/dom/navigator.rs b/components/script/dom/navigator.rs
index 9810c67a877..957abd558ec 100644
--- a/components/script/dom/navigator.rs
+++ b/components/script/dom/navigator.rs
@@ -51,6 +51,10 @@ impl<'a> NavigatorMethods for JSRef<'a, Navigator> {
     fn Platform(self) -> DOMString {
         NavigatorInfo::Platform()
     }
+
+    fn UserAgent(self) -> DOMString {
+        NavigatorInfo::UserAgent()
+    }
 }
 
 impl Reflectable for Navigator {
diff --git a/components/script/dom/navigatorinfo.rs b/components/script/dom/navigatorinfo.rs
index 8832aca8697..d8081ef134a 100644
--- a/components/script/dom/navigatorinfo.rs
+++ b/components/script/dom/navigatorinfo.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use servo_util::str::DOMString;
+use servo_util::opts;
 
 pub struct NavigatorInfo;
 
@@ -26,4 +27,11 @@ impl NavigatorInfo {
     pub fn Platform() -> DOMString {
         "".to_string()
     }
+
+    pub fn UserAgent() -> DOMString {
+        match opts::get().user_agent {
+            Some(ref user_agent) => user_agent.clone(),
+            None => "".to_string(),
+        }
+    }
 }
diff --git a/components/script/dom/webidls/Navigator.webidl b/components/script/dom/webidls/Navigator.webidl
index 16d96d53470..0ce509f4c04 100644
--- a/components/script/dom/webidls/Navigator.webidl
+++ b/components/script/dom/webidls/Navigator.webidl
@@ -23,5 +23,5 @@ interface NavigatorID {
   readonly attribute DOMString platform;
   readonly attribute DOMString product; // constant "Gecko"
   boolean taintEnabled(); // constant false
-  //readonly attribute DOMString userAgent;
+  readonly attribute DOMString userAgent;
 };
diff --git a/components/script/dom/workernavigator.rs b/components/script/dom/workernavigator.rs
index 2265b23c6bc..2d3c496048c 100644
--- a/components/script/dom/workernavigator.rs
+++ b/components/script/dom/workernavigator.rs
@@ -51,6 +51,10 @@ impl<'a> WorkerNavigatorMethods for JSRef<'a, WorkerNavigator> {
     fn Platform(self) -> DOMString {
         NavigatorInfo::Platform()
     }
+
+    fn UserAgent(self) -> DOMString {
+        NavigatorInfo::UserAgent()
+    }
 }
 
 impl Reflectable for WorkerNavigator {