A while back, Tantek Celik released A Study of Regular Polygons, which used a little-known CSS trick to create non-rectangular shapes such as triangles and pentagons with nothing more than an ordinary HTML element.

The tooltip widget design, fairly common in websites these days, uses a small triangular “speech bubble” pointer that is typically created quite easily with a background image. However, filamentgroup wanted to keep jQuery UI widgets entirely themable, and using an image for that purpose wouldn’t fit with the flexibility jQuery UI requires.

How to solve this problem without any need for images? That challenge led filamentgroup to the experimental approach using polygonal CSS, developed Image-free CSS Tooltip Pointers.

Requirements: jQuery Framework
Demo: http://www.filamentgroup.com/examples/fg-tooltip/
License: License Free