code: function (e) {
  			var $progress = $('.progress:first', this.$el),
  					complete;
  
  			if (e.lengthComputable) {
  				complete = e.loaded / e.total * 100;
  				complete = complete ? complete : 0;
  				$progress.attr('value', complete);
  				$progress.html(complete);
  			}
  		}
docs: Update progressbar while upload
  
  @param {event} e XMLHttpRequest.upload.onprogress event
  @return {void}