利用tween算法的动画方法

最近在看tween算法，封装了一个可以直接做动画的方法，调用方法类似于jQuery的animate；

$(this).iTween({"width":"200px","margin-right":"100px"},500,"BackOut",function(){
    alert("OK")
});

Object.prototype.iTween=function(styles,speed,easing,callback){
    this.element=this;
    if(this[0]){
        this.element=this[0];
    };
    if(this.element.lock){
        return;
    };
    this.element.lock=false;
    this.t = 0; //（当前时间） --  当前执行到第几次
    this.b=[];  //（初始值）-- 当前值
    this.d=100;//（持续时间）-- 执行总次数
    this.speed=speed/this.d;
    this.easing=easing||"QuartOut";
    this.name=[];
    this.value=[];
    for(var key in styles){
        if(typeof styles[key] == "string"){
            this.name.push(key);
            var start=this.element.currentStyle?this.element.currentStyle[key]:document.defaultView.getComputedStyle(this.element, false)[key];//不支持transform
            //var start=icss(this.element,key);//支持transform的另外一个方法
            this.b.push(parseInt(start));
            this.value.push(parseInt(styles[key])-parseInt(start)); //（变化量） -- 当前值和目标值中间的差值
        };
    };
    clearInterval(this.timer);
    this.timer=setInterval(function(){
        this.element.lock=true;
        this.t++;
        if(this.t>=this.d){
            clearInterval(this.timer);
            this.element.lock=false;
            callback&&callback();
            return;
        };
        for (var i=0;i<this.name.length;i++) {
            var val=Tween[this.easing](this.t,this.b[i],parseInt(this.value[i]),this.d);
            this.element.style[this.name[i]]=parseInt(val)+"px";//不支持transform
            //icss(this.element,this.name[i],parseInt(val));//支持transform的另外一个方法
        };
    }.bind(this),this.speed);
};
//tween算法
var Tween = {
    Linear: function(t,b,c,d){ return c*t/d + b; },
    QuadIn: function(t,b,c,d){
        return c*(t/=d)*t + b;
    },
    QuadOut: function(t,b,c,d){
        return -c *(t/=d)*(t-2) + b;
    },
    QuadInOut: function(t,b,c,d){
        if ((t/=d/2) < 1) return c/2*t*t + b;
        return -c/2 * ((--t)*(t-2) - 1) + b;
    },
    CubicIn: function(t,b,c,d){
        return c*(t/=d)*t*t + b;
    },
    CubicOut: function(t,b,c,d){
        return c*((t=t/d-1)*t*t + 1) + b;
    },
    CubicInOut: function(t,b,c,d){
        if ((t/=d/2) < 1) return c/2*t*t*t + b;
        return c/2*((t-=2)*t*t + 2) + b;
    },
    QuartIn: function(t,b,c,d){
        return c*(t/=d)*t*t*t + b;
    },
    QuartOut: function(t,b,c,d){
        return -c * ((t=t/d-1)*t*t*t - 1) + b;
    },
    QuartInOut: function(t,b,c,d){
        if ((t/=d/2) < 1) return c/2*t*t*t*t + b;
        return -c/2 * ((t-=2)*t*t*t - 2) + b;
    },
    QuintIn: function(t,b,c,d){
        return c*(t/=d)*t*t*t*t + b;
    },
    QuintOut: function(t,b,c,d){
        return c*((t=t/d-1)*t*t*t*t + 1) + b;
    },
    QuintInOut: function(t,b,c,d){
        if ((t/=d/2) < 1) return c/2*t*t*t*t*t + b;
        return c/2*((t-=2)*t*t*t*t + 2) + b;
    },
    SineIn: function(t,b,c,d){
        return -c * Math.cos(t/d * (Math.PI/2)) + c + b;
    },
    SineOut: function(t,b,c,d){
        return c * Math.sin(t/d * (Math.PI/2)) + b;
    },
    SineInOut: function(t,b,c,d){
        return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
    },
    ExpoIn: function(t,b,c,d){
        return (t==0) ? b : c * Math.pow(2, 10 * (t/d - 1)) + b;
    },
    ExpoOut: function(t,b,c,d){
        return (t==d) ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;
    },
    ExpoInOut: function(t,b,c,d){
        if (t==0) return b;
        if (t==d) return b+c;
        if ((t/=d/2) < 1) return c/2 * Math.pow(2, 10 * (t - 1)) + b;
        return c/2 * (-Math.pow(2, -10 * --t) + 2) + b;
    },
    CircIn: function(t,b,c,d){
        return -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;
    },
    CircOut: function(t,b,c,d){
        return c * Math.sqrt(1 - (t=t/d-1)*t) + b;
    },
    CircInOut: function(t,b,c,d){
        if ((t/=d/2) < 1) return -c/2 * (Math.sqrt(1 - t*t) - 1) + b;
        return c/2 * (Math.sqrt(1 - (t-=2)*t) + 1) + b;
    },
    ElasticIn: function(t,b,c,d,a,p){
        if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
        if (!a || a < Math.abs(c)) { a=c; var s=p/4; }
        else var s = p/(2*Math.PI) * Math.asin (c/a);
        return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
    },
    ElasticOut: function(t,b,c,d,a,p){
        if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
        if (!a || a < Math.abs(c)) { a=c; var s=p/4; }
        else var s = p/(2*Math.PI) * Math.asin (c/a);
        return (a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b);
    },
    ElasticInOut: function(t,b,c,d,a,p){
        if (t==0) return b;  if ((t/=d/2)==2) return b+c;  if (!p) p=d*(.3*1.5);
        if (!a || a < Math.abs(c)) { a=c; var s=p/4; }
        else var s = p/(2*Math.PI) * Math.asin (c/a);
        if (t < 1) return -.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
        return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*.5 + c + b;
    },
    BackIn: function(t,b,c,d,s){
        if (s == undefined) s = 1.70158;
        return c*(t/=d)*t*((s+1)*t - s) + b;
    },
    BackOut: function(t,b,c,d,s){
        if (s == undefined) s = 1.70158;
        return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
    },
    BackInOut: function(t,b,c,d,s){
        if (s == undefined) s = 1.70158; 
        if ((t/=d/2) < 1) return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;
        return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
    },
    BounceIn: function(t,b,c,d){
        return c - Tween.Bounce.easeOut(d-t, 0, c, d) + b;
    },
    BounceOut: function(t,b,c,d){
        if ((t/=d) < (1/2.75)) {
            return c*(7.5625*t*t) + b;
        } else if (t < (2/2.75)) {
            return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b;
        } else if (t < (2.5/2.75)) {
            return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b;
        } else {
            return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b;
        }
    },
    BounceInOut: function(t,b,c,d){
        if (t < d/2) return Tween.Bounce.easeIn(t*2, 0, c, d) * .5 + b;
        else return Tween.Bounce.easeOut(t*2-d, 0, c, d) * .5 + c*.5 + b;
    }
};