How to use datepicker in html form

How to use datepicker in html form for display calendar.It gives the option to select date,month and year in html form which becomes easy for user.No need to enter the date value in textbox only need to select and it will display automatically in text field.Just see an example.

<!doctype html>
<html lang="en">
  <meta charset="utf-8">
  <title>PHP Cluster jQuery UI Datepicker - Default functionality</title>
  <link rel="stylesheet" href="//">
  <script src="//"></script>
  <script src="//"></script>
  <link rel="stylesheet" href="/resources/demos/style.css">
  $(function() {
    $( "#datepicker" ).datepicker();
<p>Date: <input type="text" id="datepicker" name=”phpcluster”></p>