js中日期的加减法_javascript技巧

今天就算对JS中日期的加减法做个总结，一共两步

第一步，引入date.format.js，这个JS的作用是将日期转为指定的格式，代码如下

var dateFormat = function () {
  var  token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g,
    timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g,
    timezoneClip = /[^-+\dA-Z]/g,
    pad = function (val, len) {
      val = String(val);
      len = len || 2;
      while (val.length  99 ? Math.round(L / 10) : L),
        t:  H  0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),
        S:  ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10]
      };
 
    return mask.replace(token, function ($0) {
      return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1);
    });
  };
}();
 
// Some common format strings
dateFormat.masks = {
  "default":   "ddd mmm dd yyyy HH:MM:ss",
  shortDate:   "m/d/yy",
  mediumDate:   "mmm d, yyyy",
  longDate:    "mmmm d, yyyy",
  fullDate:    "dddd, mmmm d, yyyy",
  shortTime:   "h:MM TT",
  mediumTime:   "h:MM:ss TT",
  longTime:    "h:MM:ss TT Z",
  isoDate:    "yyyy-mm-dd",
  isoTime:    "HH:MM:ss",
  isoDateTime:  "yyyy-mm-dd'T'HH:MM:ss",
  isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'"
};
 
// Internationalization strings
dateFormat.i18n = {
  dayNames: [
    "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
    "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
  ],
  monthNames: [
    "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
    "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"
  ]
};
 
// For convenience...
Date.prototype.format = function (mask, utc) {
  return dateFormat(this, mask, utc);
};

第二步，将时间转换为毫秒进行加减计算，然后再用上面的js的转为指定的日期

var nowDate = new Date();
//加法操作
var ysDate = new Date(nowDate.getTime()-30*24*60*60*1000).format('yyyy-mm-dd');
//减法操作
var yeDate = new Date(nowDate.getTime()-24*60*60*1000).format('yyyy-m-d');

通过以上两步就实现了，JS中日期的加减法，怎么样简单吧！快去试试！

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