[1] "object getStartDate()" should be "Date getStartDate()" · Issue #3340 · whatwg/html (2018-01-17 15:56:34 +09:00) https://github.com/whatwg/html/issues/3340

[2] 312699 - Support 'getStartDate()' method in the media element. - chromium - Monorail (2018-01-17 15:57:23 +09:00) https://bugs.chromium.org/p/chromium/issues/detail?id=312699