TimelineJS is a JavaScript library for building "visually rich, interactive timelines." It is designed to be immediately functional without extensive custom code. In the most basic implementation, users construct a Google spreadsheet containing their data and tell TimelineJS where to find it. The example timeline on the project's front page was created in exactly this way. Clicking the "Make a Timeline" button on the site's landing page, users can locate step-by-step instructions showing how to create a timeline in this way. More experienced developers can customize what is displayed with their own CSS and JavaScript code using the reference material listed under Technical Documentation (found near the bottom of the landing page). The TimelineJS developers primarily test in Google Chrome but follow web standards such that the project should work in any modern browser.