Easing functions

var easing = {
		linear : function (t){
			return t;
		},
		easeInQuad: function (t) {
			return t*t;
		},
		easeOutQuad: function (t) {
			return -1 *t*(t-2);
		},
		easeInOutQuad: function (t) {
			if ((t/=1/2) < 1) return 1/2*t*t;
			return -1/2 * ((--t)*(t-2) - 1);
		},
		easeInCubic: function (t) {
			return t*t*t;
		},
		easeOutCubic: function (t) {
			return 1*((t=t/1-1)*t*t + 1);
		},
		easeInOutCubic: function (t) {
			if ((t/=1/2) < 1) return 1/2*t*t*t;
			return 1/2*((t-=2)*t*t + 2);
		},
		easeInQuart: function (t) {
			return t*t*t*t;
		},
		easeOutQuart: function (t) {
			return -1 * ((t=t/1-1)*t*t*t - 1);
		},
		easeInOutQuart: function (t) {
			if ((t/=1/2) < 1) return 1/2*t*t*t*t;
			return -1/2 * ((t-=2)*t*t*t - 2);
		},
		easeInQuint: function (t) {
			return 1*(t/=1)*t*t*t*t;
		},
		easeOutQuint: function (t) {
			return 1*((t=t/1-1)*t*t*t*t + 1);
		},
		easeInOutQuint: function (t) {
			if ((t/=1/2) < 1) return 1/2*t*t*t*t*t;
			return 1/2*((t-=2)*t*t*t*t + 2);
		},
		easeInSine: function (t) {
			return -1 * Math.cos(t/1 * (Math.PI/2)) + 1;
		},
		easeOutSine: function (t) {
			return 1 * Math.sin(t/1 * (Math.PI/2));
		},
		easeInOutSine: function (t) {
			return -1/2 * (Math.cos(Math.PI*t/1) - 1);
		},
		easeInExpo: function (t) {
			return (t==0) ? 1 : 1 * Math.pow(2, 10 * (t/1 - 1));
		},
		easeOutExpo: function (t) {
			return (t==1) ? 1 : 1 * (-Math.pow(2, -10 * t/1) + 1);
		},
		easeInOutExpo: function (t) {
			if (t==0) return 0;
			if (t==1) return 1;
			if ((t/=1/2) < 1) return 1/2 * Math.pow(2, 10 * (t - 1));
			return 1/2 * (-Math.pow(2, -10 * --t) + 2);
			},
		easeInCirc: function (t) {
			if (t>=1) return t;
			return -1 * (Math.sqrt(1 - (t/=1)*t) - 1);
		},
		easeOutCirc: function (t) {
			return 1 * Math.sqrt(1 - (t=t/1-1)*t);
		},
		easeInOutCirc: function (t) {
			if ((t/=1/2) < 1) return -1/2 * (Math.sqrt(1 - t*t) - 1);
			return 1/2 * (Math.sqrt(1 - (t-=2)*t) + 1);
		},
		easeInElastic: function (t) {
			var s=1.70158;var p=0;var a=1;
			if (t==0) return 0;  if ((t/=1)==1) return 1;  if (!p) p=1*.3;
			if (a < Math.abs(1)) { a=1; var s=p/4; }
			else var s = p/(2*Math.PI) * Math.asin (1/a);
			return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*1-s)*(2*Math.PI)/p ));
		},
		easeOutElastic: function (t) {
			var s=1.70158;var p=0;var a=1;
			if (t==0) return 0;  if ((t/=1)==1) return 1;  if (!p) p=1*.3;
			if (a < Math.abs(1)) { a=1; var s=p/4; }
			else var s = p/(2*Math.PI) * Math.asin (1/a);
			return a*Math.pow(2,-10*t) * Math.sin( (t*1-s)*(2*Math.PI)/p ) + 1;
		},
		easeInOutElastic: function (t) {
			var s=1.70158;var p=0;var a=1;
			if (t==0) return 0;  if ((t/=1/2)==2) return 1;  if (!p) p=1*(.3*1.5);
			if (a < Math.abs(1)) { a=1; var s=p/4; }
			else var s = p/(2*Math.PI) * Math.asin (1/a);
			if (t < 1) return -.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*1-s)*(2*Math.PI)/p ));
			return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*1-s)*(2*Math.PI)/p )*.5 + 1;
		},
		easeInBack: function (t) {
			var s = 1.70158;
			return 1*(t/=1)*t*((s+1)*t - s);
		},
		easeOutBack: function (t) {
			var s = 1.70158;
			return 1*((t=t/1-1)*t*((s+1)*t + s) + 1);
		},
		easeInOutBack: function (t) {
			var s = 1.70158; 
			if ((t/=1/2) < 1) return 1/2*(t*t*(((s*=(1.525))+1)*t - s));
			return 1/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2);
		},
		easeInBounce: function (t) {
			return 1 - easing.easeOutBounce (1-t);
		},
		easeOutBounce: function (t) {
			if ((t/=1) < (1/2.75)) {
				return 1*(7.5625*t*t);
			} else if (t < (2/2.75)) {
				return 1*(7.5625*(t-=(1.5/2.75))*t + .75);
			} else if (t < (2.5/2.75)) {
				return 1*(7.5625*(t-=(2.25/2.75))*t + .9375);
			} else {
				return 1*(7.5625*(t-=(2.625/2.75))*t + .984375);
			}
		},
		easeInOutBounce: function (t) {
			if (t < 1/2) return easing.easeInBounce (t*2) * .5;
			return easing.easeOutBounce (t*2-1) * .5 + 1*.5;
		}
	};