Here is the English calender date code for web page you want
For index.html, The code is
<div class="date" id="date"></div>
<script type="text/javascript" src="date/endate.js"></script>
N.B: Please insert this code where you want to show the date in home page.
Now create a folder named date and in it create a file named endate.js.
For the file endate.js, code is bellow
const options = {
year: 'numeric',
month: 'long',
day: 'numeric',
weekday: 'long',
locale: 'bn-BD'
};
const today = new Date();
const banglaDate = new Intl.DateTimeFormat('bn-BD', options).format(today);
document.getElementById('date').innerText = banglaDate + ' খ্রিস্টাব্দ ।';