JSFiddle - React, Tailwind, and code Playground

HTML

<input type="date" id="startDate" />

 <input type="date" id="endDate" />

JavaScript

$("#endDate").click(function () {
        var date1 = new Date($("#startDate").val());
        var date2 = new Date($("#endDate").val());
       console.log(date2);
        var timeDiff = Math.abs(date2.getTime() - date1.getTime());
        var diffDays = Math.ceil(timeDiff / (1000 * 3600 * 24)); 
        alert(diffDays);

    });