[whatwg] Prefetch issues

Ian Hickson ian at hixie.ch
Sun Aug 8 19:48:35 PDT 2010

On Thu, 10 Jun 2010, Eric Schurman wrote:
> As described, the link prefetching capability seems to have some 
> limitations that work counter to the performance of the page using it.
> It appears as though LINK elements are metadata elements and that these 
> may only be supported inside the HEAD of the document. If so, then this 
> is an issue in the real world, because at the time a web server flushes 
> chunks containing the HEAD section of a document, the links we would 
> want to prefetch are often not known. This is true for all the large 
> sites I've analyzed or worked at. For example, many pages on a site will 
> contain the same visual header, and we want to flush the HEAD and visual 
> header content while the server is in the process of figuring out what 
> the content of the page will be - which will contain the links we'd like 
> to prefetch.
> Am I reading this correctly?

This was indeed a limitation of the prefetch mechanism.

> One of the simplest approaches may be to add support for rel="prefetch" 
> to A and AREA's, but it's been explicitly excluded from those. Why?

No good reason. Fixed.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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