创建日历

• 由于样式需求，日历需要自定义。看网上日历一般每个月显示6行。所有用一下函数生成一个月显示的所有日期。
• 返回的数组每一项有月、日、周。当前月如果和数组月相同，样式高亮。

var getDate = function (year, month) {
  var ret = []
  var firstDay = new Date(year, month - 1, 1)
  var firstDayWeekDay = firstDay.getDay()
  var premonthDayCount = firstDayWeekDay

  for (var i = 0; i < 7 * 6; i++) {
    var date = i + 1 - premonthDayCount
    var showDate = (new Date(year, month - 1, date)).getDate()
    var thisMonth = (new Date(year, month - 1, date)).getMonth() + 1
    var thisWeek = (new Date(year, month - 1, date)).getDay()

    ret.push({
      month: thisMonth,
      date: showDate,
      week: thisWeek
    })
  }
  return ret
}