Sparkmeters are lightweight, inline graphics that give the relative value of an item. They are inspired by Edward Tufte's sparklines. They are designed to be unobtrusive and low information. Unlike sparklines, sparkmeters can't usually stand on their own, but are best used to give the relative value of a group of items (e.g. a list of skills on a resume).
This version of sparkmeters is implemented with the D3.js library. The source code is found here and licensed under a BSD-style open source license.