index.html

<!DOCTYPE html>
<html lang="en" dir="ltr">
    <head>
        <meta charset="UTF-8">
        <title>Time Difference Calculator</title>
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" type="text/css" href="style.css">
    </head>
    <body>
        <textarea rows="20" cols="60" id="input">18:45  23:15  
            17:15  22:35  
            19:30  23:35  
            17:50  23:40  
            19:35  23:45  
            08:15  12:50  
            19:30  23:50  
            18:50  23:55  
            20:25  23:59  
            18:40  23:59  
            08:15  13:30  
            15:20  19:30  
            14:00  19:10  
            18:30  23:59  
            19:10  23:59</textarea>
        <p id="output"></p>

        <script type="text/javascript" src="script.js"></script>
    </body>
</html>