Popup calendar for date entry

Am on my way with my first web app, creating a dynamic web page that is created
with my local table.  One missing element is the ability for the user to pick a
date from a calendar on the page.  

Could someone advise me on how I can have a popup calendar to pick a date for a
date entryfield on my page?  Would this be done with javascript? If yes,
appreciate any code on how it is integrated into a dynamic web page created with
plus.

Thanks for any ideas on this,