1. Create multiple dwDatePicker in one line of code.
e.g.
$('input').dxDatePicker(); // $('input').length > 0

2. Not re-create the dwDatePicker as a tag.
e.g.
$('input').dxDatePicker(); // Create the dxDatePicker
$('input').dxDatePicker('show'); // Show the dxDatePicker