Graphs and charts are a great way to break down the information at hand to the user in a descriptive and visually enticing manner. These visual structures allow you to easily simplify complex data and output easier to understand content. Everyone can use a graph or chart, however, not everyone has the right tools to create an effective one.
TufteGraph lets you configure dynamic functions and it also allows you to work with a compact API for a much faster web app. It also uses a non-core layout that is done through the use of CSS.
A simple to use, yet robust library for transforming table data into a chart. This library uses the HTML5 canvas tag and is only supported on browsers other than IE until ExCanvas gets proper text support.
With Graph-It you can easily create graphs out of raw data using Graph It! Just input the name/value pairs of the involved graph elements, and leave the rest to the script. The values can be either absolute or percentage (using two versions of script).
Canvas 3D Graph is a special type of bar graph that plot numbers in 3D
Protovis composes custom views of data with simple marks such as bars and dots. Unlike low-level graphics libraries that quickly become tedious for visualization, Protovis defines marks through dynamic properties that encode data, allowing inheritance, scales and layouts to simplify construction.
ProtoChart is a new opensource library using Prototype and Canvas to create good looking charts. This library is highly motivated by Flot, Flotr and PlotKit libraries.