This chapter provided a refresher on several fundamental technology concepts that will help you create visualizations with Chart.js. Even though Chart.js tries to hide all the underlying complexity from you, it is still a JavaScript library and basic knowledge of JavaScript, DOM, and CSS are important.

This chapter also described the main data formats used for statistical data: CSV, XML, and JSON. It also described how to load external files in these formats and how to parse them. Additionally, you learned some ways to obtain data not in these formats by extracting it from HTML pages.

In the next chapter, we will begin using Chart.js to create data visualizations.