var fx = new Object();
fx.Base = function(){};
fx.Base.prototype = { setOptions: function(options) {
	this.options = { duration: 500, onComplete: '', transition: fx.sinoidal }
	Object.extend(this.options, options || {});
	},
	go: function() { this.startTime = (new Date).getTime(); this.timer = setInterval (this.step.bind(this), 13); },
	step: function() { var time  = (new Date).getTime();
		if (time >= this.options.duration+this.startTime) {
			this.now = this.to; clearInterval (this.timer);
			this.timer = null; if (this.options.onComplete) setTimeout(this.options.onComplete.bind(this), 10);
		}else{
			var Tpos = (time - this.startTime) / (this.options.duration);
			this.now = this.options.transition(Tpos) * (this.to-this.from) + this.from;
		} this.increase();
	},
	custom: function(from, to) { if (this.timer != null) return; this.from = from; this.to = to; this.go(); },
    hide: function() { this.now = 0; this.increase(); },
	clearTimer: function() { clearInterval(this.timer); this.timer = null; }
}
fx.Layout = Class.create();
fx.Layout.prototype = Object.extend(new fx.Base(), {
	initialize: function(el, options) {
		this.el = $(el); this.el.style.overflow = "hidden"; this.el.iniWidth = this.el.offsetWidth; 
		this.el.iniHeight = this.el.offsetHeight; this.setOptions(options);
	}
});
fx.Height = Class.create();
Object.extend(Object.extend(fx.Height.prototype, fx.Layout.prototype), {	
	increase: function() { this.el.style.height = this.now + "px"; },
	toggle: function() { if (this.el.offsetHeight > 0) this.custom(this.el.offsetHeight, 0); 
		else this.custom(0, this.el.scrollHeight);
	}
});
fx.Width = Class.create();
Object.extend(Object.extend(fx.Width.prototype, fx.Layout.prototype), {	
	increase: function() { this.el.style.width = this.now + "px"; },
	toggle: function(){ 
		if (this.el.offsetWidth > 0) this.custom(this.el.offsetWidth, 0); else this.custom(0, this.el.iniWidth);
	}
});
fx.Opacity = Class.create();
fx.Opacity.prototype = Object.extend(new fx.Base(), {
	initialize: function(el, options) { this.el = $(el); this.now = 1; this.increase(); this.setOptions(options); },
	increase:function() { if (this.now == 1 && (/Firefox/.test(navigator.userAgent))) this.now = 0.9999; this.setOpacity(this.now);
	},
	setOpacity: function(opacity) {
		if (opacity == 0) this.el.style.visibility = "hidden"; else this.el.style.visibility = "visible";
		if (window.ActiveXObject) this.el.style.filter = "alpha(opacity=" + opacity*100 + ")"; this.el.style.opacity = opacity;
	},
	toggle: function() { if (this.now > 0) this.custom(1, 0); else this.custom(0, 1); }
});

fx.sinoidal = function(pos){ return ((-Math.cos(pos*Math.PI)/2) + 0.5); }
fx.linear = function(pos){ return pos; }
fx.cubic = function(pos){ return Math.pow(pos, 3); }
fx.circ = function(pos){ return Math.sqrt(pos); }