SIMILE Widgets | Timeline is an open-source tool to make timelines. You can add filters to highlight certain events, and scroll through the visual to see exactly the time that you need. Each of the events is also expandable, to see more details with each.
Create a Web App: an 8 step tutorial
CSS-Tricks has an 8 step tutorial Creating a Web App from Scratch for those who want to make interactive tools on the web. It is rich & step-by-step, walking you through how to conceive & scope your idea, and then to actually build it each step of the way.