这是我的一点JS代码，这是需要的:
var secDiff = Math.abs(Math.round((utc_date-this.premiere_date)/1000));
this.years = this.calculateUnit(secDiff,(86400*365));
this.days = this.calculateUnit(secDiff-(this.years*(86400*365)),86400);
this.hours = this.calculateUnit((secDiff-(this.years*(86400*365))-(this.days*86400)),3600);
this.minutes = this.calculateUnit((secDiff-(this.years*(86400*365))-(this.days*86400)-(this.hours*3600)),60);
this.seconds = this.calculateUnit((secDiff-(this.years*(86400*365))-(this.days*86400)-(this.hours*3600)-(this.minutes*60)),1);
我想在“前”得到日期时间，但如果DST正在使用，那么日期是1小时。我不知道如何检查夏令时是否有效。
我怎样才能知道夏令时何时开始和结束?
js库在它的time对象上提供了一个. isdst()方法。
moment#isDST检查当前时刻是否属于夏时制。
moment([2011, 2, 12]).isDST(); // false, March 12 2011 is not DST
moment([2011, 2, 14]).isDST(); // true, March 14 2011 is DST
我最近需要用UTC和DST创建一个日期字符串，根据Sheldon的回答，我把它放在一起:
Date.prototype.getTimezone = function(showDST) {
var jan = new Date(this.getFullYear(), 0, 1);
var jul = new Date(this.getFullYear(), 6, 1);
var utcOffset = new Date().getTimezoneOffset() / 60 * -1;
var dstOffset = (jan.getTimezoneOffset() - jul.getTimezoneOffset()) / 60;
var utc = "UTC" + utcOffset.getSign() + (utcOffset * 100).preFixed(1000);
var dst = "DST" + dstOffset.getSign() + (dstOffset * 100).preFixed(1000);
if (showDST) {
return utc + " (" + dst + ")";
}
return utc;
}
Number.prototype.preFixed = function (preCeiling) {
var num = parseInt(this, 10);
if (preCeiling && num < preCeiling) {
num = Math.abs(num);
var numLength = num.toString().length;
var preCeilingLength = preCeiling.toString().length;
var preOffset = preCeilingLength - numLength;
for (var i = 0; i < preOffset; i++) {
num = "0" + num;
}
}
return num;
}
Number.prototype.getSign = function () {
var num = parseInt(this, 10);
var sign = "+";
if (num < 0) {
sign = "-";
}
return sign;
}
document.body.innerHTML += new Date().getTimezone() + "<br>";
document.body.innerHTML += new Date().getTimezone(true);
<p>Output for Turkey (UTC+0200) and currently in DST: UTC+0300 (DST+0100)</p>
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