用JavaScript计算日期 [英] Calculating Date in JavaScript

问题描述

我目前正在寻找一个JavaScript中的自定义日期，我的头开始受到伤害。我有一个倒计时钟，每天晚上12点开始。我有倒计时功能使用Keith Wood的jQuery倒计时插件工作正常，但需要帮助计算当月的每个其他星期二，并在当天重置。

所有

Thansk提前

解决方案

我不得不做类似的事情（不是在JS，但算法类似）

现在，在我开始之前，澄清我假设这是不管这个月份的长短，每两周发生一次，而在第二和第四个星期二都不会，不管最后一次发生什么，这样比较简单，解决

选择过去发生此事件的日期（或第一次发生的日期），我们将在以下代码中将此日期称为 base p>

  var base = new Date（'first of first occurrence'）; 
 var one_day = 1000 * 60 * 60 * 24; //以毫秒为单位的日期长度
 
 //假设我们关心如果倒计时应该从今天开始
 //如果您正在构建日历等等，这可能会有所不同
 var date_to_check = new Date（）; 
 
 var diff_in_days = math.floor（date_to_check-base）/ one_day）; 
 var days_since_last_reset = diff_in_days％14; 
 if（days_since_last_reset == 0）{
 // date_to_check是以
 //i.e为基础的每两周周期中的同一天。今天在某个时候是你想要显示定时器
 //如果你只想在某些时间之间显示定时器，
 //在这里添加另一个检查
} else {
 //下一次重新设置（14  -  days_since_last_reset）days from date_to_check 
} 
  

或代码高尔夫球版本：

  if（Math.floor（（new Date（） -  new Date第一次出现'））/ 1000/60/60/24）％14 == 0）
 //重置/启动计时器
  

I am currently looking to calculate a custom date in JavaScript and my head is beginning to hurt thinking about it. I have a countdown clock that is to start every other Tuesday at 12pm. I have the countdown function working properly using the jQuery countdown plugin by Keith Wood but need assistance in calculating every other Tuesday of the month and having it reset on this day.

All help is greatly appreciated as always.

Thansk in advance

解决方案

I've had to do something similar (not in JS but the algorithm is similar enough)

Now, before i start, to clarify i'm assuming this is something that happens fortnightly regardless of the length of the month, and not on the second and 4th Tuesday regardless of when it last happened, which is simpler to solve

Pick a date in the past that this event has occured on (or the date of the first occurrence) , we'll call this date base in the following code

var base=new Date('date of first occurrence');
var one_day=1000*60*60*24; //length of day in ms

// assume we care about if the countdown should start today 
// this may be different if you are building a calendar etc.
var date_to_check=new Date();

var diff_in_days=math.floor(date_to_check-base)/one_day);
var days_since_last_reset= diff_in_days%14;
if(days_since_last_reset == 0){
    //date_to_check is the same day in the fortnightly cycle as base
    //i.e. today at some point is when you'll want to show the timer
    //If you only want to show the timer between certain times,
    //add another check here
}else{
    //next reset in (14 - days_since_last_reset) days from date_to_check
}

Or the code-golf-esque version:

if( Math.floor((new Date()-new Date('date of first occurrence'))/1000/60/60/24)%14 == 0 )
    //reset/start timer

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