如何在JavaScript中区分两个日期?

I'm creating an application which lets you define events with a time frame. I want to automatically fill in the end date when the user selects or changes the start date. I can't quite figure out, however, how to get the difference between the two times, and then how to create a new end Date using that difference.

我正在创建一个应用程序，它允许您定义具有时间框架的事件。我想在用户选择或更改开始日期时自动填写结束日期。但是，我不太清楚如何得到这两次时间之间的差异，以及如何使用这种差异创建新的结束日期。

16 个解决方案

#1

In JavaScript, dates can be transformed to the number of milliseconds since the epoc by calling the getTime() method or just using the date in a numeric expression.

在JavaScript中，日期可以通过调用getTime()方法或者只是在数字表达式中使用日期，来转换为自epoc以来的毫秒数。

So to get the difference, just subtract the two dates.

为了得到差值，只需要减去这两个日期。

To create a new date based on the difference, just pass the number of milliseconds in the constructor.

要根据差异创建新的日期，只需在构造函数中传递毫秒数。

var oldBegin = ...
var oldEnd = ...
var newBegin = ...

var newEnd = new Date(newBegin + oldEnd - oldBegin);

This should just work

这应该工作

EDIT: Fixed bug pointed by @bdukes

修正了@bdukes指出的错误

EDIT:

编辑:

For an explanation of the behavior, oldBegin, oldEnd, and newBegin are Date instances. Calling operators + and - will trigger Javascript auto casting and will automatically call the valueOf() prototype method of those objects. It happens that the valueOf() method is implemented in the Date object as a call to getTime().

对于行为的解释，oldBegin、oldEnd和newBegin是日期实例。调用操作符+和-将触发Javascript自动转换，并自动调用这些对象的valueOf()原型方法。碰巧valueOf()方法在Date对象中实现为对getTime()的调用。

So basically: date.getTime() === date.valueOf() === (0 + date) === (+date)

基本上，date.getTime() == date.valueOf() ==(0 +日期)===(+日期)==(+日期)

#2

JavaScript perfectly supports date difference out of the box

JavaScript完全支持日期差异。

var msMinute = 60*1000, 
    msDay = 60*60*24*1000,
    a = new Date(2012, 2, 12, 23, 59, 59),
    b = new Date("2013 march 12");


console.log(Math.floor((b - a) / msDay) + ' full days between');
console.log(Math.floor(((b - a) % msDay) / msMinute) + ' full minutes between');

---

Now some pitfalls. Try this:

现在一些隐患。试试这个:

console.log(a - 10);
console.log(a + 10);

So if you have risk of adding a number and Date, convert Date to number directly.

所以如果你有增加数字和日期的风险，直接把日期转换成数字。

console.log(a.getTime() - 10);
console.log(a.getTime() + 10);

My fist example demonstrates the power of Date object but it actually appears to be a time bomb

我的第一个例子展示了日期对象的力量，但它实际上似乎是一个定时炸弹

#3

See JsFiddle DEMO

看到JsFiddle演示

    var date1 = new Date();    
    var date2 = new Date("2015/07/30 21:59:00");
    showDiff();

function showDiff(date1, date2){

    var diff = (date2 - date1)/1000;
    var diff = Math.abs(Math.floor(diff));

    var days = Math.floor(diff/(24*60*60));
    var leftSec = diff - days * 24*60*60;

    var hrs = Math.floor(leftSec/(60*60));
    var leftSec = leftSec - hrs * 60*60;

    var min = Math.floor(leftSec/(60));
    var leftSec = leftSec - min * 60;

    document.getElementById("showTime").innerHTML = "You have " + days + " days " + hrs + " hours " + min + " minutes and " + leftSec + " seconds before death.";

setTimeout(showDiff,1000);
}

for your HTML Code:

为你的HTML代码:

<div id="showTime"></div>

#4

If you don't care about the time component, you can use .getDate() and .setDate() to just set the date part.

如果不关心时间组件，可以使用. getdate()和. setdate()来设置日期部分。

So to set your end date to 2 weeks after your start date, do something like this:

因此，要将你的截止日期设为开始日期后的两周，可以这样做:

function GetEndDate(startDate)
{
    var endDate = new Date(startDate.getTime());
    endDate.setDate(endDate.getDate()+14);
    return endDate;
}

To return the difference (in days) between two dates, do this:

要返回两个日期之间的差异(以天为单位)，请执行以下操作:

function GetDateDiff(startDate, endDate)
{
    return endDate.getDate() - startDate.getDate();
}

Finally, let's modify the first function so it can take the value returned by 2nd as a parameter:

最后，我们修改第一个函数，使其以2返回的值为参数:

function GetEndDate(startDate, days)
{
    var endDate = new Date(startDate.getTime());
    endDate.setDate(endDate.getDate() + days);
    return endDate;
}

#5

Thanks @Vincent Robert, I ended up using your basic example, though it's actually newBegin + oldEnd - oldBegin. Here's the simplified end solution:

感谢@Vincent Robert，我最终使用了您的基本示例，尽管它实际上是newBegin + oldEnd - oldBegin。下面是简化的最终解决方案:

    // don't update end date if there's already an end date but not an old start date
    if (!oldEnd || oldBegin) {
        var selectedDateSpan = 1800000; // 30 minutes
        if (oldEnd) {
            selectedDateSpan = oldEnd - oldBegin;
        }

       newEnd = new Date(newBegin.getTime() + selectedDateSpan));
    }

#6

Depending on your needs, this function will calculate the difference between the 2 days, and return a result in days decimal.

根据您的需要，这个函数将计算这2天之间的差值，并返回一个以days decimal为单位的结果。

// This one returns a signed decimal. The sign indicates past or future.

this.getDateDiff = function(date1, date2) {
    return (date1.getTime() - date2.getTime()) / (1000 * 60 * 60 * 24);
}

// This one always returns a positive decimal. (Suggested by Koen below)

this.getDateDiff = function(date1, date2) {
    return Math.abs((date1.getTime() - date2.getTime()) / (1000 * 60 * 60 * 24));
}

#7

If using moment.js, there is a simpler solution, which will give you the difference in days in one single line of code.

如果使用的时刻。js，有一种更简单的解决方案，它将在一行代码中提供不同的天数。

moment(endDate).diff(moment(beginDate), 'days');

Additional details can be found in the moment.js page

现在可以找到更多的细节。js页面

Cheers, Miguel

米盖尔,干杯

#8

function compare()
{
  var end_actual_time    = $('#date3').val();

  start_actual_time = new Date();
  end_actual_time = new Date(end_actual_time);

  var diff = end_actual_time-start_actual_time;

  var diffSeconds = diff/1000;
  var HH = Math.floor(diffSeconds/3600);
  var MM = Math.floor(diffSeconds%3600)/60;

  var formatted = ((HH < 10)?("0" + HH):HH) + ":" + ((MM < 10)?("0" + MM):MM)
  getTime(diffSeconds);
}
function getTime(seconds) {
  var days = Math.floor(leftover / 86400);

  //how many seconds are left
  leftover = leftover - (days * 86400);

  //how many full hours fits in the amount of leftover seconds
  var hours = Math.floor(leftover / 3600);

  //how many seconds are left
  leftover = leftover - (hours * 3600);

  //how many minutes fits in the amount of leftover seconds
  var minutes = leftover / 60;

  //how many seconds are left
  //leftover = leftover - (minutes * 60);
  alert(days + ':' + hours + ':' + minutes);
}

#9

function checkdate() {
    var indate = new Date()
    indate.setDate(dat)
    indate.setMonth(mon - 1)
    indate.setFullYear(year)

    var one_day = 1000 * 60 * 60 * 24
    var diff = Math.ceil((indate.getTime() - now.getTime()) / (one_day))
    var str = diff + " days are remaining.."
    document.getElementById('print').innerHTML = str.fontcolor('blue')
}

#10

alternative modificitaion extended code..

替代modificitaion扩展代码. .

http://jsfiddle.net/vvGPQ/48/

http://jsfiddle.net/vvGPQ/48/

showDiff();

function showDiff(){
var date1 = new Date("2013/01/18 06:59:00");   
var date2 = new Date();
//Customise date2 for your required future time

var diff = (date2 - date1)/1000;
var diff = Math.abs(Math.floor(diff));

var years = Math.floor(diff/(365*24*60*60));
var leftSec = diff - years * 365*24*60*60;

var month = Math.floor(leftSec/((365/12)*24*60*60));
var leftSec = leftSec - month * (365/12)*24*60*60;    

var days = Math.floor(leftSec/(24*60*60));
var leftSec = leftSec - days * 24*60*60;

var hrs = Math.floor(leftSec/(60*60));
var leftSec = leftSec - hrs * 60*60;

var min = Math.floor(leftSec/(60));
var leftSec = leftSec - min * 60;




document.getElementById("showTime").innerHTML = "You have " + years + " years "+ month + " month " + days + " days " + hrs + " hours " + min + " minutes and " + leftSec + " seconds the life time has passed.";

setTimeout(showDiff,1000);
}

#11

<html>
<head>
<script>
function dayDiff()
{
     var start = document.getElementById("datepicker").value;
     var end= document.getElementById("date_picker").value;
     var oneDay = 24*60*60*1000; 
     var firstDate = new Date(start);
     var secondDate = new Date(end);    
     var diffDays = Math.round(Math.abs((firstDate.getTime() - secondDate.getTime())/(oneDay)));
    document.getElementById("leave").value =diffDays ;
 }
</script>
</head>
<body>
<input type="text" name="datepicker"value=""/>
<input type="text" name="date_picker" onclick="function dayDiff()" value=""/>
<input type="text" name="leave" value=""/>
</body>
</html>

#12

this code fills the duration of study years when you input the start date and end date(qualify accured date) of study and check if the duration less than a year if yes the alert a message take in mind there are three input elements the first txtFromQualifDate and second txtQualifDate and third txtStudyYears

这段代码填充研究多年的持续时间当你输入开始日期和结束日期(资格雷达波日期)的研究和检查时间不到一年如果有警报消息先记住有三个输入元素txtFromQualifDate和第二txtQualifDate第三txtStudyYears

it will show result of number of years with fraction

它将显示有分数的年份的结果

function getStudyYears()
    {
        if(document.getElementById('txtFromQualifDate').value != '' && document.getElementById('txtQualifDate').value != '')
        {
            var d1 = document.getElementById('txtFromQualifDate').value;

            var d2 = document.getElementById('txtQualifDate').value;

            var one_day=1000*60*60*24;

            var x = d1.split("/");
            var y = d2.split("/");

            var date1=new Date(x[2],(x[1]-1),x[0]);

            var date2=new Date(y[2],(y[1]-1),y[0])

            var dDays = (date2.getTime()-date1.getTime())/one_day;

            if(dDays < 365)
            {
                alert("the date between start study and graduate must not be less than a year !");

                document.getElementById('txtQualifDate').value = "";
                document.getElementById('txtStudyYears').value = "";

                return ;
            }

            var dMonths = Math.ceil(dDays / 30);

            var dYears = Math.floor(dMonths /12) + "." + dMonths % 12;

            document.getElementById('txtStudyYears').value = dYears;
        }
    }

#13

If you use Date objects and then use the getTime() function for both dates it will give you their respective times since Jan 1, 1970 in a number value. You can then get the difference between these numbers.

如果您使用Date对象，然后对这两个日期使用getTime()函数，它将给出一个数字值，从1970年1月1日开始，它们各自的时间。你可以得到这些数字之间的差值。

If that doesn't help you out, check out the complete documentation: http://www.w3schools.com/jsref/jsref_obj_date.asp

如果这对您没有帮助，请查看完整的文档:http://www.w3schools.com/jsref/jsref_obj_date.asp

#14

Below code will return the days left from today to futures date.

以下代码将返回从今天到期货的剩余天数。

Dependencies: jQuery and MomentJs.

依赖性:jQuery和MomentJs。

var getDaysLeft = function (date) {
  var today = new Date();
  var daysLeftInMilliSec = Math.abs(new Date(moment(today).format('YYYY-MM-DD')) - new Date(date));
  var daysLeft = daysLeftInMilliSec / (1000 * 60 * 60 * 24);   
  return daysLeft;
};

getDaysLeft('YYYY-MM-DD');

#15

var getDaysLeft = function (date1, date2) {
   var daysDiffInMilliSec = Math.abs(new Date(date1) - new Date(date2));
   var daysLeft = daysDiffInMilliSec / (1000 * 60 * 60 * 24);   
   return daysLeft;
};
var date1='2018-05-18';
var date2='2018-05-25';
var dateDiff = getDaysLeft(date1, date2);
console.log(dateDiff);

#16

THIS IS WHAT I DID ON MY SYSTEM.

这是我在系统上做的。

var startTime=("08:00:00").split(":");
var endTime=("16:00:00").split(":");
var HoursInMinutes=((parseInt(endTime[0])*60)+parseInt(endTime[1]))-((parseInt(startTime[0])*60)+parseInt(startTime[1]));
console.log(HoursInMinutes/60);