function _autoIncrease(size, millisecond) {
    var self = this;

    var target = this._targetElement[0];
    if(!target) return;
    var progressjsId = parseInt(target.getAttribute('data-progressjs'));
    
    if (typeof window._progressjsIntervals[progressjsId] != 'undefined') {
      clearInterval(window._progressjsIntervals[progressjsId]);
    }
    window._progressjsIntervals[progressjsId] = setInterval(function() {
      _increasePercent.call(self, size);
    }, millisecond);
  }
Auto increase the progress bar every X milliseconds

@api private
@method _autoIncrease
@param {Number} size
@param {Number} millisecond