+ jQuery.timers.push(function(){
+ return z.step(from, to);
+ });
+
+ if ( jQuery.timers.length == 1 ) {
+ var timer = setInterval(function(){
+ jQuery.timers = jQuery.grep( jQuery.timers, function(fn){
+ return fn();
+ });
+
+ if ( !jQuery.timers.length )
+ clearInterval( timer );
+ }, 13);
+ }