As a former ASP.Net coder, I've missed the convenience of Microsoft's built-in Calendar Control since I switched to doing Web site development in PHP. On a recent project I needed the ability to display a calendar with dates serving as hyperlinks to selected database items. I decided to use the opportunity to write some portable PHP code that I could use in other projects.
So started Donald McArthur's work on creating a simple, easy to use calendaring system to be used in a popup inside an application. He provides all the code you'll need - the PHP code and the HTML layout/functionality you'll need to get it working.
He helps you visualize the structure of the end result HTML table with a simpler version (three cells by five cells) and explains the date functions the code uses to figure out the dates and days of the selected month.