CanPlayType()
w3schools.comOther (undocumented) values this method returns:
"perhaps" - There is, of course, a chance the codec is supported. Or not.
"why bother" - Everyone will die anyway, browser support is meaningless in the grand scheme of things.
"ask again later" - Computer needs to be shaken vigorously and restarted. This value is returned with annoying frequency.