Loading and parsing remote data

In this section, we want to visualize real data rather as in sample dataset; hence, we need to understand how to load data from remote locations. In JavaScript, you can use the native XMLHttpRequest (XHR) object to fetch data within your application. D3 implements not only a wrapper for the native XHR call, but it also implements wrappers for loading different data types and parsing them automatically.

Here is a list of some high-level wrappers in D3:

• d3.text(url[, mimeType][, callback]): This loads a plain text file with a mimeType from an URL; the data is handed over as a string to the callback where the parsing must be done manually

• d3.json(url[, callback]): This loads and parses a JSON file from an URL; the data is passed as an object in the callback

• d3.xml(url[, mimeType][, callback]): Loads and parses an XML file from an URL, the data is passed as an object in the callback

• d3.html(url[, callback]): This loads and parses an HTML file from an URL; the...