In 2014 I had an idea, didn't go anywhere though: "I've been working on a project to implement a feature similar to PDF native 'custom annotations,' but using

In 2014 I had an idea, didn't go anywhere though: "I've been working on a project to implement a feature similar to PDF native 'custom annotations,' but using an external JSON file. The idea is to allow a more hacker-friendly way to add javascript-powered interactivity to a PDF file, and allow a js-based-document-viewer to interact with other elements in a web page. Somewhat like using an external subtitles-file for a video instead of hard-coded subs, allowing you to use things like HTML5 tracks for generating events etc. (manipulating PDFs internal workings is hard work for those who create documents/content, and the JS support is old-fashioned, if I remember rightly).." https://groups.google.com/forum/#!topic/mozilla.dev.pdf-js/24DK2E7I5nc https://groups.google.com/forum/#!topic/mozilla.dev.pdf-js/2... I think mostly I liked PDF's precise, fixed control over layout, and wanted to be able to program some js onClick callbacks on top of it in an easy way. Maybe sometime I will revisit the ideas, see if there was something there.