I originally conceived of these as an alternative to images of buttons, tabs, or standard form controls. Soon after, IE and later Navigator opened up their DOMs to allow greater customization of these interface elements, but they're still inconsistent.

I wanted to have complete control of interface elements' appearance through CSS while avoiding disparate browser DOMs. As a result, I came up with the following:
 

Buttons documented in ASP & JavaScript:


 

Tabs documented in ASP & JavaScript: