Disable ranges of time in jQuery DatePicker

calendar_disable_ranges.js

var holidays = [ ['04/5/2015', '04/11/2015'], ['4/26/2015', '4/28/2015'], ['4/30/2015', '5/8/2015'] ];

function highlightDays(date) {
  for (var i = 0; i < holidays.length; i++) {
    var in_range = (new Date(holidays[i][0]) <= date) && (new Date(holidays[i][1]) >= date);
    if (in_range) {
      return [false];
    }
  }
  
  return [true];
}

$(function () {
  $("#dp").datepicker({
    minDate: 0,
    dateFormat: 'mm/dd/yy',
    inline: true,
    numberOfMonths: [1, 2],
    dayNamesMin: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'],
    beforeShowDay: highlightDays,
  });
});

Improved a piece of code from http://jsfiddle.net/CxNNh/78/
Not focused on performance neither style!