I have a similar question as HTML5 video, fallback to flash if no .ogv file
But my question is I want to fallback to flash if browser CAN'T OPEN .ogv file (not DOESN'T SUPPORT ogv). Suppose my html already has preset fallback codes below source elements, can I instruct browsers continue executing these preset fallback codes if all sources are failed to open (i.e. no source network state)?
You can sniff whether browser supports or does not support OGV beforehand before playing it: