1、ios <audio>不播放
Vue.prototype.playAudio = function (audioSrc, cb) {
  var audio = new Audio()
  audio.preload = ‘auto‘
  audio.src = audioSrc
  if (window.WeixinJSBridge) {
      console.log(‘audio支持‘)
      WeixinJSBridge.invoke(‘getNetworkType‘, {}, function (e) {
        audio.load()
        audio.play()
      }, false)
  } else {
      console.log(‘audio不支持‘)
      document.addEventListener("WeixinJSBridgeReady", function () {
          WeixinJSBridge.invoke(‘getNetworkType‘, {}, function (e) {
            audio.load()
            audio.play()
          })
      }, false)
  }
  cb && cb(audio)
}

2、预加载图片
beforeCreate () {
      const cdnUrl = ‘https://xxx/image‘
      let imgs = [
        `${cdnUrl}/home-bg.gif`,
        `${cdnUrl}/btn-close.png`,
        `${cdnUrl}/hand-down.png`,
      ]
      imgs.forEach((item) => {
        let image = new Image()
        image.src = item
        image.onload = () => {
          this.count++
        }
      })
  },

    /**scroll隐藏底部 */
    hideBtBox () {
      var that = this
      window.onscroll = function(){
        var scrollTop = document.documentElement.scrollTop||document.body.scrollTop //滚动高
        var windowHeight = document.documentElement.clientHeight || document.body.clientHeight //视图高
        var scrollHeight = document.documentElement.scrollHeight||document.body.scrollHeight //文档高
        if ((scrollTop + windowHeight + 30) >= scrollHeight) {
          that.isShowBt = false
        } else {
          that.isShowBt = true
        }
      }
    },