Resumable.js基于 HTML5 File API 的文件上传工具

Resumable.js 是一个 JS 库提供了多路同步、稳定和可恢复的文件上传，基于 HTML5 File API

示例代码：

var r = new Resumable({
  target:'/api/photo/redeem-upload-token', 
  query:{upload_token:'my_token'}
});
// Resumable.js isn't supported, fall back on a different method
if(!r.support) location.href = '/some-old-crappy-uploader';