JavaScript实现给定时间相加天数的方法

/*** 时间相加处理函数* @param date 需要计算的时间(xxxx-xx-xx)* @param plusDays 要加的天数(整数)*/function calcuDate(date, plusDays) {  var dateArray = date.split("-");  var year = +dateArray[0];  var month = +dateArray[1];  var day = +dateArray[2];  var oriDay = day;  var secondMonthDays = ((year%4 === 0 && year%100 !== 0) || year%400 === 0) ? 29 : 28;  while(plusDays>0) {    oriDay = day    day += plusDays;    switch(month) {      case 4:      case 6:      case 9:      case 11:        if(day > 30) {          plusDays -= (30-oriDay)+1;          month++;          day = 1;        } else {          plusDays = 0;        }      break;      case 2:        if(day > secondMonthDays) {          plusDays -= (secondMonthDays-oriDay)+1;          month++;          day = 1;        } else {          plusDays = 0;        }      break;      default:        if(day > 31) {          plusDays -= (31-oriDay)+1;          day = 1;          month++;        } else {          plusDays = 0;        }    }    if(month>12) {      month = 1;      year++;    }  }  return createTimeString(year, month, day);}