The web blogs are writing about a colour contrast checker which you can check if the contrast between the foreground and the background is enough. Really a goodie. (via)
But what got me going was the slider function
in that tool. Quite nice implementation, first I thought it was an
Flash thingy but then i read about it. Nice one with some DOM and HTML.
Could be useful for a lot of web applications I think. See also this demo.