upload.js

$.ajax({
  'url':'/judge/api/' + api_key + '/add_pkg',
  'type':'POST',
  'data':pkg,
  'cache':false,
  'processData':false,
  'contentType':false,
  'xhr':function(){
    var xhr = new XMLHttpRequest();
    xhr.upload.addEventListener('progress',function(e){
      var prog = Math.min(100,e.loaded / pkg.size * 100);
      j_bar.css('width',prog + '%');
    });
    return xhr;
  },
  'success':function(res){
    j_result_spin.hide();
    j_result.text(JSON.stringify(res,null,' '));
    j_result.show();
  },
});