$.fx.speeds._default)) / 1000
return this.anim(properties, duration, ease, callback)
}
$.fn.anim = function(properties, duration, ease, callback) {
var key, cssValues = {}, cssProperties, transforms = '',
that = this,
wrappedCallback, endEvent = $.fx.transitionEnd
//动画持续时间默认值
if (duration === undefined) duration = 0.4
//如果浏览器不支持CSS3的动画，则duration=0，意思就是直接跳转最终值
if ($.fx.off) duration = 0
//如果properties是一个动画名keyframe
if (typeof properties == 'string') {
// keyframe animation
cssValues[animationName] = properties
cssValues[animationDuration] = duration + 's'
cssValues[animationTiming] = (ease
关键词：zepto是啥