What is "webvtt"

WebVTT (Web Video Text Tracks) is a W3C standard for displaying timed text in connection with the HTML5 <track> element. The early drafts of its specification were written by WHATWG in 2010, after discussions about what caption format should be supported by HTML5, the main options being the relatively mature, XML-based TTML or an entirely new but more lightweight standard based on the popular SRT format. The final decision was for the new standard, initially called WebSRT (Web Subtitle Resource Tracks). It shared the .srt file extension and was "broadly based on" (parts of) the SubRip format, though not fully compatible with it. The prospective format was later renamed WebVTT. In the January 13, 2011 version of the HTML5 Draft Report, the <track> tag was introduced and the specification was updated to document WebVTT cue text rendering rules. The WebVTT specification is still in draft stage but the basic features are already supported by all major browsers.