Re: inline declarative manifest, was Re: New manifest spec - ready for FPWD?

On Tue, 17 Dec 2013 17:06:57 +0100, Boris Zbarsky <bzbarsky@mit.edu> wrote:

> On 12/17/13 3:29 AM, Jonas Sicking wrote:
>> This is a good point. Would this have performance implications for
>> down-level browsers? I don't know if prescanners etc in contemporary
>> browsers are smart enough to ignore <script> tags that use a non-JS
>> type attribute.
>
> Gecko's is not.  Not least because as far as I can tell scripts with  
> unknown type are in fact always loaded,

In my testing this appears to not be the case.

http://software.hixie.ch/utilities/js/live-dom-viewer/saved/2697

This gives nothing in the Network tab in Firefox or in my TCP inspector.

I think this is the same as what the spec requires and what at least  
WebKit/Blink/Presto also do.

See step 7 in  
http://www.whatwg.org/specs/web-apps/current-work/multipage/scripting-1.html#prepare-a-script  
(the fetch happen in step 14).


But it seems you are correct about the behavior of the speculative parser  
in Gecko:

http://software.hixie.ch/utilities/js/live-dom-viewer/saved/2698

> just not executed, and block the parser while they're loading, so you do  
> in fact want to preload them! I'm not sure whether that behavior is  
> Gecko-specific or not, but I suspect not: I recall people using unknown  
> script types to do preloading in general.
>
> -Boris
>


-- 
Simon Pieters
Opera Software

Received on Wednesday, 18 December 2013 10:58:37 UTC