js获取n天之后的日期

function getDateAfter_n(initDate, days, flag) {if(!days) {return initDate;}initDate = initDate.replace(/-/g, '');flag = $.trim(flag);var date;// 是否设置了起始日期  if(!$.trim(initDate)) { // 没有设置初始化日期，就默认为当前日期  date = new Date();} else {var year = initDate.substring(0, 4);var month = initDate.substring(4, 6);var day = initDate.substring(6, 8);date = new Date(year, month - 1, day); // 月份是从0开始的  }date.setDate(date.getDate() + days);var yearStr = date.getFullYear();var monthStr = ("0" + (date.getMonth() + 1)).slice(-2, 8); // 拼接2位数月份  var dayStr = ("0" + date.getDate()).slice(-2, 8); // 拼接2位数日期  var result = "";if(!flag) {result = yearStr + "-" + monthStr + "-" + dayStr;} else {result = yearStr + flag + monthStr + flag + dayStr;}return result;}