JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo"></div>

JavaScript

var iquit =new Date(2013, 1, 15);
    today=new Date();
    //Get 1 day in milliseconds
    var one_day=1000*60*60*24;
    var day_numeric=Math.ceil((today.getTime()-iquit.getTime())/(one_day));
    //Calculate difference btw the two dates, and convert to days
    document.getElementById("foo").innerHTML = "<p>"+day_numeric+
            " days have gone by since you quit smoking!</p>"+
            "<p>You have saved "+ day_numeric*7+" pounds</p>";