--- a/dom/animation/TimingParams.h
+++ b/dom/animation/TimingParams.h
@@ -62,17 +62,18 @@ struct TimingParams
     }
     return result;
   }
 
   static void ValidateIterationStart(double aIterationStart,
                                      ErrorResult& aRv)
   {
     if (aIterationStart < 0) {
-      aRv.Throw(NS_ERROR_DOM_TYPE_ERR);
+      aRv.ThrowTypeError<dom::MSG_ENFORCE_RANGE_OUT_OF_RANGE>(
+        NS_LITERAL_STRING("iterationStart"));
     }
   }
 
   // mDuration.isNothing() represents the "auto" value
   Maybe<StickyTimeDuration> mDuration;
   TimeDuration mDelay;      // Initializes to zero
   TimeDuration mEndDelay;
   double mIterations = 1.0; // Can be NaN, negative, +/-Infinity