Make negative transition-duration and animation-duration values invalid (Bug 16806)

Author: Sylvain Galineau

css3-animations/Overview.src.html

@@ -548,8 +548,8 @@ <h3 id="animation-duration-property">
 	<p>
 		The initial value is ''0s'', 
 		meaning that the animation takes no time. 
-		A negative value for 'animation-duration' is treated as ''0s''. 
-		In this case 'animation-fill-mode' still applies, 
+		A negative value for 'animation-duration' renders the declaration invalid. 
+		When the duration is ''0s'' 'animation-fill-mode' still applies, 
 		so an animation that fills backwards 
 		will show the value of the 0% keyframe during any delay period, 
 		and an animation that fills forwards will retain the value specified at the 100% keyframe, 

css3-transitions/Overview.src.html

@@ -373,7 +373,7 @@ <h3 id=transition-duration-property><a id=the-transition-duration-property->
         </tbody>
       </table>
       <p>
-        This property specifies how long the transition from the old value to the new value should take. By default the value is '0s', meaning that the transition is immediate (i.e. there will be no animation). A negative value for <code class="property">transition-duration</code> is treated as '0s'.
+        This property specifies how long the transition from the old value to the new value should take. By default the value is '0s', meaning that the transition is immediate (i.e. there will be no animation). A negative value for <code class="property">transition-duration</code> renders the declaration invalid.
       </p>
 
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