JSFiddle - React, Tailwind, and code Playground

HTML

<button id="test">See the Tab</button>
<div class="varianceData"></div>

JavaScript

$('#test').click(function () {

    // Here are the two dates to compare
    var date1 = '29-10-2015';
    var date2 = '29-12-2015';
    var Targetvalue = parseFloat("1000000");
    var dealjson = '[{"dealdate":"25-11-2015","cost":200000}]';

    // First we split the values to arrays date1[0] is the year, [1] the month and [2] the day
    date1 = date1.split('-');
    date2 = date2.split('-');

    // Now we convert the array to a Date object, which has several helpful methods
    date1 = new Date(date1[2], date1[1], date1[0]);
    date2 = new Date(date2[2], date2[1], date2[0]);

    // We use the getTime() method and get the unixtime (in milliseconds, but we want seconds, therefore we divide it through 1000)
    date1_unixtime = parseInt(date1.getTime() / 1000);
    date2_unixtime = parseInt(date2.getTime() / 1000);

    // This is the calculated difference in seconds
    var timeDifference = date2_unixtime - date1_unixtime;

    // in Hours
    var timeDifferenceInHours = timeDifference / 60 / 60;

    // and finaly, in days :)
    var timeDifferenceInDays = timeDifferenceInHours / 24;
    var timeDifferenceInWeeks = Math.round(timeDifferenceInDays / 7);
    // alert(timeDifferenceInDays/7);
    TargetPerweek = Targetvalue / timeDifferenceInWeeks;
    //Math.round(timeDifferenceInWeeks);
    TargetPerweek = Math.round(TargetPerweek * 100) / 100;
    var string = "<table data-role='table' class='ui-responsive'><thead><tr><th>Week</th><th>Target</th><th>Achieved</th></tr></thead>";
    for (var i = 1; i <= timeDifferenceInWeeks; i++)
    string = string + "<tr><th>Week" + i + "</th><td>" + TargetPerweek + "</td><td></td></tr>";

    string = string + "</table>";
    $('.varianceData').html(string);

});