One of my favorite widgets is the Datepicker in JQuery UI.

Simple Syntax and you have a pop calendar to keep your users out of trouble:

  $( function() {
    $( "#CapCase_ClosureDate" ).datepicker();

And there are many other useful widgets in JQuery UI

From Wikipedia, the free encyclopedia

“jQuery UI is a collection of GUI widgets, animated visual effects, and themes implemented with jQuery (a JavaScript library), Cascading Style Sheets, and HTML.[5] According to JavaScript analytics service, Libscore, jQuery UI is used on over 197,000 of the top one million websites, making it the second most popular JavaScript library.”