What is d3.js?
More information about d3.js - http://tech.queryhome.com/49964/overview-about-d3-js-part1
What is Reusable charts ?
Reusable chart is nothing but the charts should already created we can simply get benefit of the charts.we don't need to spend time to create a charts from scratch.
Some of the Reusable charts for d3.js.
NVD3 is one of the reusable charts for d3.js.They create some basic frequent charts like pie chart,bar chart,bubble chart,stacked bar chat etc.. using d3.js with the name of nvd3.js
What is the required library for nvd3?
Download d3.v3 here. It is the only required library for nvd3.
See the example page for nvd3 here : http://nvd3.org/examples/index.html
Also,Download Nvd3 examples here as Zip format : https://github.com/novus/nvd3/zipball/master
C3.js is the another reusable charts for d3.js.This library also already created some predefined charts like line charts,bar charts etc. with using the d3.js.
Download the latest version of C3.js here
Or Load using Scripts ans css
<!-- Load c3.css -->
<link href="/path/to/c3.css" rel="stylesheet" type="text/css">
<!-- Load d3.js and c3.js -->
<script src="/path/to/d3.v3.min.js" charset="utf-8"></script>
See the more reference from the official site : http://c3js.org/
Visit the example pages for reusable charts here : http://c3js.org/examples.html
Both nvd3 and c3.js are famous reusable charts.All chats are implemented by using d3 library.So whenever user need to use these libraries they simply need to copy the coding and change their own data.That sol your change is ready.
Data will be created either json or csv.Based on the graph they created some sample data for each graph.So you need to create your own data with the same format which they created.