How to calculate the number of the week from the start and end date period?

Question

the main idea is to get the number of the week between two dates (from a period of start date and end date)! Something like that: if the period is 01-05-2020 to 31-05-2020 and in the data picker I chouse 08-05-2020 result will be 2, the second week.

can someone help with that can't figure out by my self, thank you!

here is JS date picker code line with setting up period 01-05-2020 to 31-05-2020, how to echo out from this js code number of week for future php usage or input value?

js

<!-- js -->
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js' type='text/javascript'></script>
<!-- Datepicker -->
<link href='https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.9.0/css/bootstrap-datepicker.min.css' rel='stylesheet' type='text/css'>
<script src='https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.9.0/js/bootstrap-datepicker.min.js' type='text/javascript'></script>


<script type="text/javascript">
$(document).ready(function(){

  $('#datepicker').datepicker({
    format: "dd/mm/yyyy",
    startDate: new Date('2020-5-1'),
    endDate: new Date('2020-5-31')
  });

});
</script>

html

<div class="form-group">
<label for="formGroupExampleInput">Date of sale</label>
<input type="text" name="dos" value="<?php echo $doc; ?>" class="form-control" id='datepicker' id="formGroupExampleInput">
</div>

score 0 · Answer 1 · answered May 27 '20 at 15:33

Accordingly to your main idea, you can use date-fns library to get the difference between date in weeks.

// import date-fns library
<script src="https://cdnjs.cloudflare.com/ajax/libs/date-fns/2.0.0-alpha0/date_fns.min.js"></script>

Then you can:

let diffCalendarWeeks = dateFns.differenceInCalendarWeeks(new Date(2020,4,31), new Date(2020,4,1));
let diffWeeks = dateFns.differenceInWeeks(new Date(2020,4,31), new Date(2020,4,1))
console.log(diffCalendarWeeks); //5
console.log(diffWeeks); // 4

See date-fns documentation https://date-fns.org/v2.0.0-alpha.1/docs/differenceInCalendarWeeks

If you want to know the week number within specified month you can see the difference between the selected date and first date.

let selectedDate = new Date(2020, 4, 15);
let startOfMonth = dateFns.startOfMonth(new Date());
var selectedWeek = dateFns.differenceInWeeks(selectedDate, startOfMonth) + 1;
console.log(selectedWeek);

Or you can try this answer if fits you better Getting current week of current month

It isn't 31st of april but 31st of May, since months for the Date api are 0-index based. — Kluivert, May 21 '21 at 11:58

score 0 · Accepted Answer · answered May 31 '20 at 15:23

Thanks, I found a solution to my problem. Here it is, maybe someone needed..

<script>
function diff_weeks(dt2, dt1) 
 {

  var diff =(dt2.getTime() - dt1.getTime()) / 1000;
  diff /= (60 * 60 * 24 * 7);
  return Math.abs(Math.round(diff));

 }

dt1 = new Date(2014,10,2);
dt2 = new Date(2014,10,11);
console.log(diff_weeks(dt1, dt2));

dt1 = new Date("June 13, 2014 08:11:00");
dt2 = new Date("October 19, 2014 11:13:00");
console.log(diff_weeks(dt1, dt2));
<script>

lnk. https://www.w3resource.com/javascript-exercises/javascript-date-exercise-47.php

How to calculate the number of the week from the start and end date period?

2 Answers2