More jQuery.speed() fixes.

diff --git a/src/fx/fx.js b/src/fx/fx.js
index 0ede5ee..d83bf0d 100644 (file)
--- a/src/fx/fx.js
+++ b/src/fx/fx.js
@@ -363,7 +363,7 @@ jQuery.extend({
                        easing: fn && easing || easing && easing.constructor != Function && easing
                };
 
-               opt.duration = (opt.duration.constructor == Number ? 
+               opt.duration = (opt.duration && opt.duration.constructor == Number ? 
                        opt.duration : 
                        { slow: 600, fast: 200 }[opt.duration]) || 400;