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"|'[^']*'/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 < len) val = "0" + val; return val; }; // Regexes and supporting functions are cached through closure return function (date, mask, utc) { var dF = dateFormat; // You can't provide utc if you skip other args (use the "UTC:" mask prefix) if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/d/.test(date)) { mask = date; date = undefined; } // Passing date through Date applies Date.parse, if necessary date = date ? new Date(date) : new Date; if (isNaN(date)) throw SyntaxError("invalid date"); mask = String(dF.masks[mask] || mask || dF.masks["default"]); // Allow setting the utc argument via the mask if (mask.slice(0, 4) == "UTC:") { mask = mask.slice(4); utc = true; } var _ = utc "get", d = date[_ + "Date"](), D = date[_ + "Day"](), m = date[_ + "Month"](), y = date[_ + "FullYear"](), H = date[_ + "Hours"](), M = date[_ + "Minutes"](), s = date[_ + "Seconds"](), L = date[_ + "Milliseconds"](), o = utc ? 0 : date.getTimezoneOffset(), flags = { d: d, dd: pad(d), ddd: dF.i18n.dayNames[D], dddd: dF.i18n.dayNames[D + 7], m: m + 1, mm: pad(m + 1), mmm: dF.i18n.monthNames[m], mmmm: dF.i18n.monthNames[m + 12], yy: String(y).slice(2), yyyy: y, h: H % 12 || 12, hh: pad(H % 12 || 12), H: H, HH: pad(H), M: M, MM: pad(M), s: s, ss: pad(s), l: pad(L, 3), L: pad(L > 99 ? Math.round(L / 10) : L), t: H < 12 ", tt: H < 12 ", T: H < 12 ", TT: H < 12 ", Z: utc " : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""), o: (o > 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！
以上所述就是本文的全部内容了，希望大家能够喜欢。
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