Video tutorials
Narrated walkthroughs of Open Lab and of building tasks in the lab.js builder. Each has subtitles in 12 languages, chapters and a transcript, the files to follow along directly under the player, and a link to its docs page.
Files for this video
- ↓ media.jsonThe builder file this video starts from (the end of the previous video).
- ↓ styling.jsonThe builder file at the end of this video: the two keys, the task's CSS, the practice label and the two headers.
The lab.js builder: a reaction-time task, step by step
Styling with HTML and CSS
3:08 · narrated, with subtitles in 12 languages · recorded in November 2026
The response keys drawn as keys with the kbd tag, in the colours of the circles through classes of your own in the task's CSS, and a label on the practice trials with a header in both frames that keeps the circles in place; saved, and updated on Open Lab with the builder's upload shortcut.