[whatwg] Script-related feedback
ian at hixie.ch
Wed Jul 24 11:18:01 PDT 2013
On Wed, 9 Jan 2013, Anne van Kesteren wrote:
> On Wed, Jan 9, 2013 at 9:32 PM, Ian Hickson <ian at hixie.ch> wrote:
> > Advantages of putting this in JS over multipart:
> > - it's backwards-compatible
> > - it's easier to parse a static barrier than a multipart/*'s wacky
> > syntax.
> > - it doesn't impact any of the current fetching logic, since it's
> > still just one resource instead of introducing a layer in between
> > <script>'s logic and the JS logic.
> > - it automatically works anywhere you can use JS, not just where HTTP is
> > involved.
> > - it can be shimmed more easily (if you trust the JS not to have
> > arbitrary injection and be written with the shim in mind, especially).
> > - it doesn't run into weird problems like what if a part has the wrong
> > MIME type.
> > - it's way easier to deploy (authors hate having to set MIME types).
> > - it doesn't run into the problem that all UAs have historically ignored
> > the MIME type of script.
> big downside though. Furthermore, multipart logic, however weird, is a
> sunk cost both on consumer and producer side, whereas introducing
> /*@BREAK*/ seems like a very steep uphill battle. And actually <img> is
> a precedent for checking a MIME type before sniffing/executing and it
> hasn't been much of a problem. (The problems there were mostly figuring
> out how SVG should work.)
Yeah, but the multipart logic has pretty big disadvantages -- mainly the
opposite of the advantages for a built-in feature:
- not backwards compatible
- not as simple to understand, use, implement, or spec
- doesn't really work outside HTTP
- harder to shim
- more edge cases to define (e.g. what if the MIME types of the parts
- requires setting MIME types, which authors hate
use multipart/* logic to do incremental rendering of HTML, we don't use it
for incremental rendering of images (only for animating them), why would
we use it for incremental execution of script? I think scripts, just like
image formats, HTML, XML, etc, should have built-in support for
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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