原生JS实现一个滑动插件

基本思路是封装一个Slider类， 拥有默认初始配置参数。
Slider.prototype(原型链上)拥有实现滑动的方法，通过监听手势，实现滑动的效果。
比较复杂的滑动效果， 可以使用Swiper.js 来实现。

/* PollyFill for iOS 5.* */if (!Function.prototype.bind) {    Function.prototype.bind = function (oThis) {        var args = Array.prototype.slice.call(arguments, 1)        var f2bind = this        var fnop = function () {}        var bound = function () {            return f2bind.apply(this instanceof fnop && oThis                ? this                : oThis,                args.concat(Array.prototype.slice.call(arguments)))        }        fnop.prototype = this.prototype        bound.prototype = new fnop()        return bound    }}// 添加浏览器前缀function prefix(style) {    var vendor = (function() {        var transArr = ['transform', 'webkitTransform', 'MozTransform', 'msTranform', 'OTransform'],            vendors = ['', 'webkit', 'Moz', 'ms', 'O'],            elementStyle = document.createElement('div').style        for (var i = 0; i < vendors.length; i++) {            if (transArr[i] in elementStyle) {                return vendors[i]            }        }        return false    })()    if (vendor === false) return false    if (vendor === '') return style    return vendor + style.charAt(0).toUpperCase() + style.substr(1)}var TRANSFORM = prefix('transform'),    TRANSITION = prefix('transition')var Slider = function(options) {    // 初始化配置参数    this.options = $.extend({        slideWrap: '.pages',    // 容器        slideItem: '.page', // 滑动单元的元素        direction: 'Y', // 滑动的方向        effect: 'slide',    // 滑动的效果        triggleDist: 100,   // 触发滑动的手指移动最小位移        followFinger: true, // 是否跟随手指移动        duration: .4,   // 翻页的延时        currentIdx: 0   // 初始显示的页码    }, options)    var EffectDict = {        'slide' : ['slide', 'slide'],        'scale' : ['slide', 'scale']    }    this.pagesWrap = document.querySelector(this.options.slideWrap)    this.pages = document.querySelectorAll(this.options.slideItem)    this.hook = this.options.slideController    this._total = this.pages.length    this._pageX = 0    this._pageY = 0    this._distance = 0  // 页面之间切换的距离    this._moveDist = 0  // touch 滑动的距离    this._supportTouch = 'ontouchend' in window    this._touching = false    this._enter = this[EffectDict[this.options.effect][0]].bind(this)    this._leave = this[EffectDict[this.options.effect][1]].bind(this)    this._init()    this._bindEvents()}Slider.prototype = {    _init: function() {        var width = this.pagesWrap.clientWidth,            height = this.pagesWrap.clientHeight,            currentIdx = this.options.currentIdx,            pages = this.pages,            total = this._total,            distance = this._distance = (this.options.direction == 'Y' ? height : width)        // 初始化各个 page 的位置        for (var i = 0; i < this._total; i++) {            if (i == currentIdx) {                pages[i].classList.add('current')            } else {                this._enter(pages[i], i < currentIdx ? -distance : distance, 2)            }        }    },    _bindEvents: function() {        var _this = this,            pagesWrap = this.pagesWrap        var events = this._supportTouch ? 'touchstart touchmove touchend touchcancel' : 'mousedown mousemove mouseup mousecancel'        events.split(' ').forEach(function(e) {            pagesWrap.addEventListener(e, _this)        })        window.addEventListener('orientationchange', this)        window.addEventListener('resize', this)    },    handleEvent: function(e) {        switch (e.type) {            case 'orientationchange':            case 'resize':                this._init()                break            case 'touchstart':            case 'mousedown':                this._start(e)                break            case 'touchmove':            case 'mousemove':                this._move(e)                break            case 'touchend':            case 'touchcancel':            case 'mouseup':            case 'mousecancel':                this._end(e)                break        }    },    _start: function(e) {        if (this._touching) {            e.preventDefault()            e.stopPropagation()            return        }        this._touching = true        this._moveDist = 0        var touches = (this._supportTouch ? e.touches[0] : e),            distance = this._distance,            enter = this._enter        var $current = this.pages[this.options.currentIdx],            $next = $current.nextElementSibling,            $prev = $current.previousElementSibling        this._pageX = touches.pageX        this._pageY = touches.pageY        $current.style.zIndex = 1        if ($next) {            $next.style.zIndex = 2            enter($next, distance)        }        if ($prev) {            $prev.style.zIndex = 2            enter($prev, -distance)        }    },    _move: function(e) {        e.preventDefault()        if (!this._touching) return        var touches = (this._supportTouch ? e.touches[0] : e),            direction = this.options.direction,            distance = this._distance        var currentIdx = this.options.currentIdx,            $current = this.pages[this.options.currentIdx],            $next = $current.nextElementSibling,            $prev = $current.previousElementSibling,            xDist = touches.pageX - this._pageX,            yDist = touches.pageY - this._pageY,            enter = this._enter,            leave = this._leave,            moveDist = this._moveDist = (direction == 'X' ? xDist : yDist)        if (this.options.followFinger) {            $next && enter($next, moveDist + distance)            $prev && enter($prev, moveDist - distance)            // 因为不能翻页，所以制造拖动困难的效果            if ((currentIdx == 0 && moveDist > 0) || (currentIdx == this._total && moveDist < 0)) {                return this.slide($current, moveDist / 4)            }            leave($current, moveDist)        }    },    _end: function(e) {        var move = this._moveDist,            distance = this._distance,            triggleDist = this.options.triggleDist,            enter = this._enter,            $current = this.pages[this.options.currentIdx],            $next = $current.nextElementSibling,            $prev = $current.previousElementSibling        this._touching = false        this._enter($current, 0)        $next && enter($next, distance)        $prev && enter($prev, -distance)        if ($next && move < -triggleDist && this.hook.shouldGoToNext($current)) return this._next()        if ($prev && move > triggleDist && this.hook.shouldGoToPrev($current)) return this._prev()    },    _next: function() {        this.go2page(this.options.currentIdx + 1)    },    _prev: function() {        this.go2page(this.options.currentIdx - 1)    },    go2page: function(idx) {        var $current = this.pages[this.options.currentIdx],            $target = this.pages[idx],            enter = this._enter,            leave = this._leave,            distance = (idx < this.options.currentIdx ? this._distance : -this._distance)        $($target).one('webkitTransitionEnd', function() {            $current.classList.remove('current')            $target.classList.add('current')            this.hook.didGoToPage($target, $current)        }.bind(this))        leave($current, distance)        enter($target, 0)        this._moveDist = 0        this.options.currentIdx = idx    },    /**     * 切页的效果     * 目前只支持两种效果：     * 1. Slide（普通的滑动）     * 2. Scale（缩放滑动）     */    slide: function(el, val, need) {        need = need || 1        el.style.webkitTransition = (need == 1) ? 'all 0.4s' : ''        el.style[TRANSFORM] = 'translate3d(' + ('Y' == this.options.direction ? '0, ' + val + 'px' : (val + 'px, 0')) + ',0)'    },    scale: function(el, val) {        el.style.webkitTransition = 'all 0.4s'        el.style[TRANSFORM] = 'scale(' + (1 - Math.round(Math.abs(val) / this._distance / 4*100) / 100) + ') translateZ(0)'    }}var slideController = {    shouldGoToPrev: function(el) {        return false;    },    shouldGoToNext: function(el) {        return false;;    },    didGoToPage: function(el, prevEl) {        return false;    }}function query(selector){    return document.querySelector(selector);}