Re: Browsers downloaded linked files regardless of media type

On Wed, Jan 26, 2011 at 11:40:54AM -0800, Antony Kennedy wrote:
> Safari and Firefox (which are the only I've tested so far) both opt to
> download a file with an unknown or unsupported media type, and then
> ignore the contents. The spec does not mention at all what the
> behaviour should be – it only states how the files should be parsed.
> Regardless of whether the <link> tag or @import rules are used, the
> file is still downloaded by the browser.
> 
>  <link rel="stylesheet" href="test.css" media="boat" />
> 
>  @import url(test.css) boat;
> 
> Both of these commands will download a file (you can observe this in a
> proxy, firebug, or the web inspector).
> 
> Any performance gain by serving files only to those devices that can
> make use of them are bypassed in this instance.
> 
> Is this a browser bug? Should the spec be more specific (pun intended)?
> Or is there an instance in which the downloading of these files might
> be useful?

I'm inclined to consider this outside of the scope of CSS, and that
it's a browser performance bug.

CSS specs probably shouldn't say that user agents mustn't have any
functionality other than rendering the current document.

However, being outside of the scope of CSS doesn't preclude adding an
informative note about it if we wanted to, hinting to UA implementers
that here's an opportunity to reduce network traffic if they so wish.

pjrm.

Received on Thursday, 27 January 2011 00:37:15 UTC