docs: function _date_str(n){
  
  	function _zero_fill(n){
  	    var ret = n;
  	    if( ret < 10 ){
  		ret = '0' + ret;
  	    }
  	    return ret;
  	}
  	
  	var now = new Date();
  	var dts = now.getFullYear() + '/' +
  	    _zero_fill(now.getMonth() +1) + '/' +
  	    _zero_fill(now.getDate()) + ' ' +
  	    _zero_fill(now.getHours()) + ':' +
  	    _zero_fill(now.getMinutes()) + ':' +
  	    _zero_fill(now.getSeconds());
  	return dts;
      }