Re: Feature Strings

Current browsers ignore tags they don't understand. That's why  
<canvas>, <video> and <audio> are considered practical in terms of  
fallback.

- Elliott Sprehn



On Apr 19, 2007, at 1:28 PM, Jeff Schiller wrote:

>
> Brad,
>
> Thanks.
>
> I see that Canvas has the ability to provide fallback content [1]  
> like:
>
> <canvas><img src="sorry.png"/></canvas>
>
> I just wanted to verify that existing user agents (IE included) would
> parse the <img/> if they didn't understand what <canvas/> means.
> Someone probably can give me a Yes/No answer there.
>
> I notice <video> says the same thing, though I think there is a
> slightly incorrect statement in [2].  Shouldn't
>
> "Content may be provided inside the video element so that older Web
> browsers, which do not support video, can display text to the user
> informing them of how to access the video contents. User agents should
> not show this fallback content to the user."
>
> be
>
> "Content may be provided inside the video element so that older Web
> browsers, which do not support video, can display text to the user
> informing them of how to access the video contents. User agents that
> support the <video> element should not show this fallback content to
> the user."
>
> I think the fallback content mechanism within WHATWG HTML5 makes
> perfect sense as long as older user agents would automatically display
> the fallback content (which I'm assuming that has already been
> verified given the overall philosphy of the WHATWG HTML5 document).
> Given that, I don't see <switch> as necessary.
>
> Regards,
> Jeff
>
> [1] http://www.whatwg.org/specs/web-apps/current-work/multipage/ 
> section-the-canvas.html#the-canvas
> [2] http://www.whatwg.org/specs/web-apps/current-work/multipage/ 
> section-video.html#video
>
> On 4/19/07, Brad Fults <bfults@neatbox.com> wrote:
>> Section 2.3.3 of the Web Apps 1.0 draft [1] seems to indicate that
>> DOM3 Core's feature strings [2], including getFeature() and
>> isSupported(0, will be relied upon for such things.
>>
>> [1] - http://www.whatwg.org/specs/web-apps/current-work/multipage/ 
>> section-common.html#dom-feature
>> [2] - http://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMFeatures
>>
>>
>> --
>> Brad Fults
>>
>