function createTweens( animation, props ) {
    jQuery.each( props, function( prop, value ) {
      var collection = ( tweeners[ prop ] || [] ).concat( tweeners[ "*" ] ),
      index = 0,
      length = collection.length;
      for ( ; index < length; index++ ) {
        if ( collection[ index ].call( animation, prop, value ) ) {
          // we're done with this property
          return;
        }
      }
    });
  } 

function( prop, value ) {
  var end, unit,
  //根據(jù)css特征值獲取緩動動畫結(jié)構(gòu)
  tween = this.createTween( prop, value ),
  parts = rfxnum.exec( value ),
  target = tween.cur(),
  start = +target || 0,
  scale = 1,
  maxIterations = 20;
  if ( parts ) {
    end = +parts[2];
    unit = parts[3] || ( jQuery.cssNumber[ prop ] ? "" : "px" );
    //非像素單位的屬性
    if ( unit !== "px" && start ) {
      // 從一個非零起點開始迭代，
      //對于當前屬性，如果它使用相同的單位這一過程將是微不足道
      // 后備為end，或一個簡單的常量
      start = jQuery.css( tween.elem, prop, true ) || end || 1;
      do {
        //如果前一次迭代為零，加倍，直到我們得到*東西* 
        //使用字符串倍增因子，所以我們不會偶然看到scale不改變
        scale = scale || ".5";
        // 調(diào)整和運行
        start = start / scale;
        jQuery.style( tween.elem, prop, start + unit );
        // 更新scale, 默認0或NaN從tween.cur()獲取
        // 跳出循環(huán)，如果scale不變或完成時, 或者我們已經(jīng)覺得已經(jīng)足夠了
      } while ( scale !== (scale = tween.cur() / target) && scale !== 1 && --maxIterations );
    }
    tween.unit = unit;
    tween.start = start;
    //如果提供了+=/-=記號，表示我們正在做一個相對的動畫
    tween.end = parts[1] ? start + ( parts[1] + 1 ) * end : end;
    }
    return tween;
  }]
}; 

function Tween( elem, options, prop, end, easing ) {
  return new Tween.prototype.init( elem, options, prop, end, easing );
}
jQuery.Tween = Tween;
Tween.prototype = {
  constructor: Tween,
  init: function( elem, options, prop, end, easing, unit ) {
    this.elem = elem;
    this.prop = prop;
    this.easing = easing || "swing";
    this.options = options;
    this.start = this.now = this.cur();
    this.end = end;
    this.unit = unit || ( jQuery.cssNumber[ prop ] ? "" : "px" );
  },
  cur: function() {...},
  run: function( percent ) {...}
};
Tween.prototype.init.prototype = Tween.prototype; 

cur: function() {
  var hooks = Tween.propHooks[ this.prop ];

  return hooks && hooks.get ?
  hooks.get( this ) :
  Tween.propHooks._default.get( this );
}, 

//如果有動畫時長則使用jQuery.easing計算出緩動動畫進度eased，否則進度eased為percent
//并根據(jù)進度得到當前動畫位置now
if ( this.options.duration ) {
  this.pos = eased = jQuery.easing[ this.easing ](
    percent, this.options.duration * percent, 0, 1, this.options.duration
    );
} else {
  this.pos = eased = percent;
}
this.now = ( this.end - this.start ) * eased + this.start;

//設(shè)置css特征值
if ( hooks && hooks.set ) {
  hooks.set( this );
} else {
  Tween.propHooks._default.set( this );
}
return this; 

   tick = function() {
      ...
        length = animation.tweens.length;
      for ( ; index < length ; index++ ) {
        animation.tweens[ index ].run( percent );
      }
　　　　　　　...
    } 

opt = {
    complete: fnction(){...},//動畫執(zhí)行完成的回調(diào)
    duration: 400,//動畫執(zhí)行時長
    easing: "swing",//動畫效果
    queue: "fx",//動畫隊列
    old: false/fnction(){...},
} 

remaining = Math.max( 0, animation.startTime + animation.duration - currentTime ),
temp = remaining / animation.duration || 0,
percent = 1 - temp