Fix window.performance.now()

2 files changed, 4 insertions, 3 deletions

diff --git a/components/script/dom/performance.rs b/components/script/dom/performance.rs
index 60f5abfec95..3fc094eeb65 100644
--- a/components/script/dom/performance.rs
+++ b/components/script/dom/performance.rs
@@ -47,9 +47,10 @@ impl<'a> PerformanceMethods for JSRef<'a, Performance> {
         Temporary::new(self.timing.clone())
     }
 
+    // https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/HighResolutionTime/Overview.html#dom-performance-now
     fn Now(self) -> DOMHighResTimeStamp {
-        let navStart = self.timing.root().NavigationStartPrecise() as f64;
-        (time::precise_time_s() - navStart) as DOMHighResTimeStamp
+        let navStart = self.timing.root().NavigationStartPrecise();
+        (time::precise_time_ns() as f64 - navStart) * 1000000u as DOMHighResTimeStamp
     }
 }
 
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index ec12d983918..2a245ea228a 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -394,7 +394,7 @@ impl Window {
             browser_context: DOMRefCell::new(None),
             performance: Default::default(),
             navigation_start: time::get_time().sec as u64,
-            navigation_start_precise: time::precise_time_s(),
+            navigation_start_precise: time::precise_time_ns() as f64,
             screen: Default::default(),
             session_storage: Default::default(),
             timers: TimerManager::new()