HTML and CSS Reference
In-Depth Information
aregoingtousethe
canPlayType()
methodofthe
video
objecttotelluswhichtypeofaudio
file to load.
The
canPlayType()
method takes a single parameter, a MIME type. It returns a text string of
maybe
,
probably
, or nothing (an empty string).
"""
(nothing)
This is returned if the browser knows the type cannot be rendered.
maybe
maybe
This is returned if the browser does not confidently know that the type can be displayed.
probably
This is returned if the browser knows the type can be displayed using an
audio
or
video
element.
Wearegoingtousethesevaluestodetermine whichmediatypetoloadandplay.Forthesake
ofthisexercise, wewillassumethatboth
maybe
and
probably
equate to
yes
.Ifweencounter
either result with any of our three MIME types (
video/webm
,
video/mp4
,
video/ogg
), we will
return the extension associated with that MIME type so that the sound file can be loaded.
Inthefollowingfunction,
video
representstheinstanceof
HTMLVideoElement
thatwearego-
ing to test. The
returnExtension
variable represents that valid extension for the first MIME
typefoundthathasthevalueof
maybe
or
probably
returnedfromthecallto
canPlayType()
:
function
function
supportedVideoFormat
(
video
) {
var
var
returnExtension
=
""
;
iif
(
video
.
canPlayType
(
"video/webm"
)
==
"probably"
||
video
.
canPlayType
(
"video/webm"
)
==
"maybe"
) {
returnExtension
=
"webm"
;
}
else
else iif
(
video
.
canPlayType
(
"video/mp4"
)
==
"probably"
||
video
.
canPlayType
(
"video/mp4"
)
==
"maybe"
) {
returnExtension
=
"mp4"
;
}
else
else iif
(
video
.
canPlayType
(
"video/ogg"
)
==
"probably"
||
video
.
canPlayType
(
"video/ogg"
)
==
"maybe"
) {
returnExtension
=
"ogg"
;
}
return
return
returnExtension
;
}