gistfile1.js

new Effect.Parallel([
	new Effect.Move(previousBackdrop, { sync: true, x:w, mode: 'absolute' }),
	new Effect.Move(nextBackdrop, { sync: true, x:0, mode: 'absolute' }),
	new Effect.Fade(previousTabHilight, {sync:true}),
	new Effect.Appear(nextTabHilight, {sync:true}),
	new Effect.Morph(previousTab, {style:'normal'}),
	new Effect.Morph(nextTab, {style:'selected'})
], { 
	duration: 0.8,
	transition: Effect.Transitions.easeOutQuad,
	beforeStart: function () {Accordion.animating = true;},
	afterFinish: function () {
		previousBackdrop.hide();
		previousTab.className = '';
		nextTab.className = 'selected';
		Accordion.animating = false;
	}
});