js获取当前月的第一天、最后一天

/**
 * 获取当前月第一天
 */
function currentMonthFirst() {
  var date = new Date()
  date.setDate(1)
  return date
}

/**
 * 获取当前月最后一天
 */
function currentMonthLast() {
  var date = new Date()
  var currentMonth = date.getMonth()
  var nextMonth = ++currentMonth
  var nextMonthFirstDay = new Date(date.getFullYear(), nextMonth, 1)
  var oneDay = 1000 * 60 * 60 * 24
  return new Date(nextMonthFirstDay - oneDay)
}