I have a hidden form like this

HTML

<h2> First Date</h2>
<input type="hidden" class="datepicker" id="startDate" value="29-10-2015" />

<h2> Second Date</h2>
<input type="hidden" class="datepicker" id="endDate" value="29-12-2015" />

<button type="button" id="test">Click It</button>
<p>Total Weeks</p>

JAVAScript

$("input").datepicker();

    $('#test').click(function () {
        var end = $('#endDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();
        var start = $('#startDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();

        var $weekDiff = Math.floor((end - start + 1) / (1000 * 60 * 60 * 24) / 7);

        alert('Total Weeks :'+$weekDiff);
    });

When I am printing the Dates in hidden input field from Database and it is in the format that I have pasted here

JSFiddle

I have a hidden form like this

HTML

<h2> First Date</h2>
<input type="hidden" class="datepicker" id="startDate" value="29-10-2015" />

<h2> Second Date</h2>
<input type="hidden" class="datepicker" id="endDate" value="29-12-2015" />

<button type="button" id="test">Click It</button>
<p>Total Weeks</p>

JAVAScript

$("input").datepicker();

    $('#test').click(function () {
        var end = $('#endDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();
        var start = $('#startDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();

        var $weekDiff = Math.floor((end - start + 1) / (1000 * 60 * 60 * 24) / 7);

        alert('Total Weeks :'+$weekDiff);
    });

When I am printing the Dates in hidden input field from Database and it is in the format that I have pasted here

JSFiddle

• javascript
• jquery

• So what is the issue? – hindmost Commented Oct 13, 2015 at 11:08
• 1 How to get the date from jQuery UI datepicker – Andreas Commented Oct 13, 2015 at 11:09

5 Answers 5

Convert to ms and divide by ms per week.

// date1 = $('#startDate').datepicker('getDate');
// date2 = $('#endDate').datepicker('getDate');

function nWeeks(date1, date2) {
    var WEEK = 1000 * 60 * 60 * 24 * 7;

    var date1ms = date1.getTime();
    var date2ms = date2.getTime();

    var diff = Math.abs(date2ms - date1ms);

    return Math.floor(diff / WEEK);
}

Here is a reference about JS date objects.

Here is a simple way to do it:

$("input").datepicker()

$('#test').on('click', () => {
  const end = $('#endDate').datepicker('getDate'),
    start = $('#startDate').datepicker('getDate'),
    $weekDiff = Math.floor((end - start + 1) / (1000 * 60 * 60 * 24) / 7);

  $('#total').html($weekDiff)
})

<script src="https://ajax.googleapis./ajax/libs/jquery/2.0.2/jquery.min.js"></script>
<script src="https://code.jquery./ui/1.10.3/jquery-ui.min.js"></script>
<h2> First Date</h2>
<input type="text" class="datepicker" id="startDate" value="12/10/2015" />
<h2> Second Date</h2>
<input type="text" class="datepicker" id="endDate" value="12/29/2015" />
<button type="button" id="test">Click It</button>
<p>Total Weeks</p><span id="total"></span>

You are trying to convert JS strings to integers in mathematical expressions, which will result in NaN.

So you need to first do Date.parse( string ).

With your fiddle it would be:

$("input").datepicker();

$('#test').click(function () {
    var end = $('#endDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();
    var start = $('#startDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();

    end = Date.parse( end );
    start = Date.parse( start );

    alert( [end, start] );

    var $weekDiff = Math.floor((end - start + 1) / (1000 * 60 * 60 * 24) / 7);

    alert('Total Weeks :'+$weekDiff);
});

With es6, and some shortening:

$("input").datepicker();

$('#test').click( () => {
    const [end, start] = ["#endDate", "startDate"]
        .map( e => Date.parse( e.datepicker({ dateFormat: 'dd-mm-yyyy'}).val() ) );

    const diff = Math.floor((end - start + 1) / (1000 * 60 * 60 * 24) / 7);
    console.log('Total Weeks :' + diff);
});

It works for me.

$('#test').click(function () {
    var end = $('#endDate').datepicker({dateFormat: 'dd-mm-yyyy'}).val();
    var start = $('#startDate').datepicker({dateFormat: 'dd-mm-yyyy'}).val();
    var aDate1 = end.split('-');
    var aDate2 = start.split('-');
    end = Date.UTC(aDate1[2], aDate1[1] - 1, aDate1[0]);
    start = Date.UTC(aDate2[2], aDate2[1] - 1, aDate2[0]);
    alert(Math.floor((end - start) / (1000 * 60 * 60 * 24)));
});

You can try something like this.

$("input").datepicker();

$('#test').click(function () {
    var end = $('#endDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();
    var start = $('#startDate').datepicker({ dateFormat: 'dd-mm-yyyy'}).val();

    var $weekDiff = Math.floor((end - start + 1) / (1000 * 60 * 60 * 24) / 7);

    alert(daydiff(parseDate(start), parseDate(end)));
});



function parseDate(str) {
    var mdy = str.split('/')
    return new Date(mdy[2], mdy[0]-1, mdy[1]);
}

function daydiff(first, second) {
    return Math.round((second-first)/(1000*60*60*24) / 7);
}

Updated your jsfiddle