How to use datetimepicker in code.
1. Add this jquery.ui.datetimepicker.js file in your project
2. Add datepicker.css file in your stylesheet

1. Example1

<input type='text' id='date_time' name='date_time'></input>

<script type='text/javascript'>
  $(document).ready(function(){
 $('#date_time').datetimepicker();
});
</script>

This will call datetimepicker onclick of input field.

2.Example2
  By default select specified date 

 <input type='text' id='date_time' name='date_time'></input>
<script type='text/javascript'>
  $(document).ready(function(){
 $('#date_time').datetimepicker({
    defaultDate : new Date(2012,07,01)
});
});
</script>

3.Example3
  By default select specified time
$('#date_time').datetimepicker({
   hour : 8,
   minute : 30,
   ampm : 'PM'
});

4. Example 4
  Disable previous dates.

    var date = new Date();
    var m = date.getMonth();
    var d = date.getDate();
    var y = date.getFullYear();
  $('#date_time').datetimepicker({
     minDate : new Date(y, m, d)
  });