[dblohm7]

"When you start using a seemingly mature HTML5 api, and find that it doesn't work as expected in all browsers, what recourse does one have?"

File bugs. Chromium and Firefox are not black boxes.

[jfoster]

Very often the bugs have been filed by someone else. Years ago.

A few examples that come to mind:

https://code.google.com/p/chromium/issues/detail?id=67587

https://code.google.com/p/chromium/issues/detail?id=178297

https://bugs.webkit.org/show_bug.cgi?id=102914

[ndesaulniers]

or here's an opportunity to start contributing to open source!