how to use jquery calendar code example

Example 1: datepicker using jquery

<!doctype html>
<html lang = "en">
   <head>
      <meta charset = "utf-8">
      <title>jQuery UI Datepicker functionality</title>
      <link href = "https://code.jquery.com/ui/1.10.4/themes/ui-lightness/jquery-ui.css"
         rel = "stylesheet">
      <script src = "https://code.jquery.com/jquery-1.10.2.js"></script>
      <script src = "https://code.jquery.com/ui/1.10.4/jquery-ui.js"></script>
      
      <!-- Javascript -->
      <script>
         $(function() {
            $( "#datepicker-13" ).datepicker();
            $( "#datepicker-13" ).datepicker("show");
         });
      </script>
   </head>
   
   <body>
      <!-- HTML --> 
      <p>Enter Date: <input type = "text" id = "datepicker-13"></p>
   </body>
</html>

Example 2: jquery 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>
 
  </script>
</head>
<body>
 
<p>Date: <input type="text" id="datepicker"></p>
 
 
</body>
</html>