Calculating the difference between two dates

Question

I have tried like this

<script type="text/javascript">
     var date2=02/09/2009;
     var date1=03/12/2009;
     var diff = date1.getDate()-date2.getDate();
     alert (diff);

</script>

but it's not working, is that reason getDate will work only for Date?

How to find the difference between these two dates? Am I not able use this function, because I am adding javascript in salesforce CRM apex pages?

Edit 1 : infact this too not working

<script type="text/javascript">
     var date2= new Date ("02/09/2009");
     var date1= new Date ("04/09/2009");
     var diff = date1.getDate()-date2.getDate();
     alert (diff);

</script>

Edit 2 : its not working too ...

<script type="text/javascript">
     var date2= "02/09/2009";
     var date1= "04/09/2009";
     var diff2 =    new Date(Date.parse("03/12/2009")-
                        Date.parse("02/09/2009")).toLocaleDateString();

// var new_date = new Date (1970, 01, 01); // var diff3 = diff2.getDate(); alert (diff2);

</script>

Answer 1

Here is explained how to find the difference between two dates in javascript

Answer 2

diff.setTime(Math.abs(date1.getTime() - date2.getTime()));

timediff = diff.getTime();

weeks = Math.floor(timediff / (1000 * 60 * 60 * 24 * 7));
timediff -= weeks * (1000 * 60 * 60 * 24 * 7);

days = Math.floor(timediff / (1000 * 60 * 60 * 24)); 
timediff -= days * (1000 * 60 * 60 * 24);

hours = Math.floor(timediff / (1000 * 60 * 60)); 
timediff -= hours * (1000 * 60 * 60);

mins = Math.floor(timediff / (1000 * 60)); 
timediff -= mins * (1000 * 60);

secs = Math.floor(timediff / 1000); 
timediff -= secs * 1000;

alert(weeks + " weeks, " + days + " days, " + hours + " hours, " + mins + " minutes, and " + secs + " seconds");

Answer 3

1. getDate() returns the day of the month, in your case: 9 and 12.

2. You should explicitely define date objects via the following. Months are 0-based, therefore 0 = January, 1 = February ...

   var date2 = new Date(2009, 1, 9);

3. These are numbers, not a string. When you want to use a string for the date, then you need exactly that format, nothing is optional:

   var newDate = new Date("month day, year hours:minutes:seconds"); var date2 = new Date("february 9, 2009 00:00:00");

[Edit] Complete solution, if dates are in format mm/dd/yyyy, and the difference should be in days:

<script type="text/javascript">
    function daysFromString(dateString)
    {
        // split strings at / and return array
        var splittedString = dateString.split("/");
        // make a new date. Caveat: Months are 0-based in JS
        var newDate = new Date(parseInt(splittedString[2], 10), parseInt(splittedString[0], 10)-1, parseInt(splittedString[1], 10));
        // returns days since jan 1 1970
        return Math.round(newDate.getTime() / (24*3600*1000));
    }

    var dateString2 = "02/09/2009";
    var dateString1= "03/12/2009";
    var dateDays1 = daysFromString(dateString1);
    var dateDays2 = daysFromString(dateString2);
    var diff = dateDays1 - dateDays2;
    alert (diff);
</script>

Answer 4

getDate is a method of Date object. as any docs clearly state it returns the day of the month in range 0 to 31. it wouldn't make sense to try to subtract one from the other if it's not the same month.

Answer 5

use Date.parse(date1) - Date.parse(date2)

Answer 6

Hi,

date2 = 02/09/2009 is not considered to be a date. it works this way. First it devides 02/09, it returns 0.2222222222222222 and its been divided by 2009 (0.2222222222222222/2009). finally you got an result date2 = 0.0001106133510314695. same way it calculates the result for date1.

this is not a valid operation. If you wanted to define the date. make sure that, you placed the data in a right date format.

use either new Date() or Date.parse("02/09/2009")

Edit:

   new Date(Date.parse("03/12/2009")-Date.parse("02/09/2009")).toLocaleDateString() Or
   new Date(date1- date2).toLocaleDateString()

isnt that work..??

Edit :

may be this will work.. can u try this..

 Date.parse("03/12/2009")-Date.parse("02/09/2009") / (24*60*60*1000)

and it returns 31 days

it seems working for me.. but in my time zone it took 03/12/2009 as 3rd month 11th day and year 2009

(24*60*60*1000) = Number of milliseconds per day

Cheers

Ramesh Vel

Answer 7

<script type="text/javascript">
function GetD()
{
    var date1 = new Date ( 2009 , 09 , 02 );
    var date2 = new Date ( 2009 , 12 , 03 );        

    var diff = days_between (date1,date2);
    alert ( diff );
}
function days_between(date1, date2) {

    // The number of milliseconds in one day
    var ONE_DAY = 1000 * 60 * 60 * 24;

    // Convert both dates to milliseconds
    var date1_ms = date1.getTime();
    var date2_ms = date2.getTime();

    // Calculate the difference in milliseconds
    var difference_ms = Math.abs(date1_ms - date2_ms);

    // Convert back to days and return

    return Math.round(difference_ms/ONE_DAY);
}
</script>

Answer 8

yes. You must use Date object, like this

var d = new Date(2009,9,19); //19th october, months are 0-based
var d2 = new Date(2009,10,12);
var diff = (d2 - d)/60000;  //diff in minutes
alert(diff / 24);   //difference in hours

Answer 9

<script language="JavaScript">
<!--
function dstrToUTC(ds) {
 var dsarr = ds.split("/");
 var mm = parseInt(dsarr[0],10);
 var dd = parseInt(dsarr[1],10);
 var yy = parseInt(dsarr[2],10);
 return Date.UTC(yy,mm-1,dd,0,0,0);
}

function datediff(ds1,ds2) {
 var d1 = dstrToUTC(ds1);
 var d2 = dstrToUTC(ds2);
 var oneday = 86400000;
 return (d2-d1) / oneday;
}

// test cases are below

var a; var b;

a = "01/09/1999";
b = "01/10/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "01/12/1999";
b = "01/19/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "01/19/1999";
b = "01/12/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "01/03/1999";
b = "01/13/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "04/30/1999";
b = "05/01/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "05/30/1999";
b = "06/01/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "02/28/1999";
b = "03/01/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "02/28/2000";
b = "03/01/2000";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "01/01/1999";
b = "12/31/1999";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "01/01/2000";
b = "12/31/2000";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

a = "12/15/1999";
b = "01/15/2001";
document.write("From "+a+" to "+b+" is "+datediff(a,b)+" day(s)<br>");

// -->
</script>

Answer 10

Try

var diff2 =    Date.parse("03/12/2009") - Date.parse("02/09/2009");

It will give you the difference between the dates in milliseconds. Divide this number by 86,400,000 and the difference will be in days.

Answer 11

Many of the answers given will work, but if you're going to do a lot of date manipulation may I suggestion taking a look at my Date Extentions here:

DP DateExtensions

Once you load them in you might do this (using your initial example):

<script type="text/javascript">
     var date2 = new Date ("02/09/2009");
     var date1 = new Date ("04/09/2009");
     var diff = date1.diff(date2, "seconds");
     alert (diff);
</script>

You can get the difference in any of the following dateparts:

• milliseconds: Milliseconds.
• seconds: Seconds.
• minutes: Minutes.
• quarterhours: 15 minutes.
• warhols: 15 minutes (of fame).
• halfhours: 30 minutes.
• hours: Hours.
• days: Days.
• weeks: Weeks (periods of 7 days).
• businessdays: Days excluding Saturday and Sunday. Note that holidays are NOT considered.
• businessweeks: Business weeks (periods of 5 business days).
• wholeweeks: Weeks from Sunday to Saturday. Only whole weeks will be counted.
• months: Months.
• years: Years

The extensions give a ton of other functions as well for all your date math and manipulation needs.

I've found the extensions insanely useful, hope they help.