index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">

</head>
<body>
   
            <div class="div" id="main">

                <div>
                    <h3 class="title">Start:</h3> <h3 class="title" style="padding-left:150px">End:</h3>
                </div>
                <div id="dates_field">
                    <div id="date0">
                        
                        <input type="datetime-local"  id="startDate" onblur="compare(`${this.parentElement.id}`,'startDate',`${this.value}`);"/>
                        
                        <input type="datetime-local"  id="endDate" onblur="compare(`${this.parentElement.id}`,'endDate', `${this.value}`);" />
                    </div>
                </div>
                
                <div><button id="addBtn">Add Another</button></div>
                <div><button id="submitBtn">Submit</button></div>
                <script src="main.js"></script>
                
            </div>
        
    
    
</body>
</html>