[whatwg] Challenging canvas.supportsContext

Simon Pieters simonp at opera.com
Tue Jun 25 00:54:57 PDT 2013

On Mon, 24 Jun 2013 23:31:59 +0200, Dean Jackson <dino at apple.com> wrote:

> Also, the presence of window.WebGLRenderingContext doesn't necessarily  
> indicate
> that WebGL is supported. On iOS for example, that object is available in  
> Safari
> but calling getContext('webgl') fails. The supportsContext method would  
> allow
> authors to easily detect this case.

Since supportsContext is not supported in Safari on iOS, authors cannot  
use it to detect this case at all.

We could say in the spec that if a UA knows it cannot create a specific  
context, it must hide the corresponding interface object. This does  
basically the same thing as supportsContext, except that it would also  
work for pages that already do feature detection based on the interface  

Simon Pieters
Opera Software

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