[whatwg] <link rel=icon width="" height="">

Kornel Lesinski kornel at osiolki.net
Thu May 8 17:02:29 PDT 2008

On Thu, 08 May 2008 03:17:38 +0100, Ian Hickson <ian at hixie.ch> wrote:

> I've added a "sizes" attribute to <link> for the "icon" keyword.

The spec now contains:

> If multiple icons are provided, the user agent must select the most  
> appropriate icon according to the media and sizes attributes. If there  
> are multiple equally appropriate icons, user agents must use the first  
> one declared in tree order.

Does this disallow composing .ico files from multiple separate files? UAs  
like Fluid or Prism can't know which sizes OS is going to use, so all  
valid ico sizes are 'equally appropriate'.

Also this algorithm doesn't match current browser behaviour, is this  
I did a quick test with a bunch of random favicons:
* Opera 9.5b2 loads all icons (that's pretty bad if one decides to provide  
Leopard's monsterous 300KB icons) and displays last icon loaded,
* Firefox 3b5 picks last icon regardless of attributes. It loads all icons  
when I reload page after restoring session.
* WebKit nightly and Fluid pick last icon that has type attribute (even if  
type is bogus), or just last if none have type.

I'm afraid that this could cause trouble (every visitor downloading icon  
that's 20–300 times larger than typical favicon). Why not use  
rel=application-icon or rel=appicon?

I don't like the "any" keyword. SVG icons are scallable, but it's not the  
same as being usable at any size. For example Tango icons project provides  
PNG for 16, 22 and 32px icons in addition to SVG, because lines and finer  
details in SVG become illegible at small sizes.

Does the specified size imply that UA is required to display icon at given  
size only? (i.e. is "any" obligatory to have icon scaled at all?) What if  
sizes attribute is absent?

regards, Kornel Lesiński

More information about the whatwg mailing list