Esempio base di codice javascript per inserire un campo data con controllo, mediante la libreria jQuery UI, con Datepicker:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>jQuery UI Datepicker - Default functionality</title>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<link rel="stylesheet" href="/resources/demos/style.css">
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<script>
$( function() {
$( "#datepicker" ).datepicker();
} );
</script>
</head>
<body>
<p>Date: <input type="text" id="datepicker"></p>
</body>
</html>
Altri esempi si possono vedere nella pagina: https://jqueryui.com/datepicker/