JS实现预加载视频音频/视频获取截图（返回canv(2)

// 参考资料
// HTML5的Video标签的属性,方法和事件汇总
// http://www.cnblogs.com/TF12138/p/4448108.html
# 使用
import loadMedia from '@/common/js/load-media'
let loadVideo = new loadMedia({
 type: 'video',
 url: 'http://xmqvip1-1253933147.file.myqcloud.com/chat/video/60/2017/09/29/qgj1c8K7oaYn-SCVideo-Merged.mp4',
 callback: handleCallback
})
function handleCallback (res) {
    console.log(res)
    // canplaythrough
    if (res.code === 0) {
    }
    // error
    if (res.code === 2) {
    }
   }