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Re: [webcomponents] More backward-compatible templates

From: Glenn Maynard <glenn@zewt.org>
Date: Fri, 2 Nov 2012 16:16:31 -0500
Message-ID: <CABirCh9SZW+avQK3dw+nFO1mHJe_G=hdDQsjtt+uxQJiaHaM5A@mail.gmail.com>
To: Maciej Stachowiak <mjs@apple.com>
Cc: "public-webapps@w3.org WG" <public-webapps@w3.org>
I'm coming into this late, but what's the purpose of allowing nested
templates (this part doesn't seem hard) and scripts in templates, and what
does putting a script within a template mean?  (It sounds like it would run
the script when you clone the template, but at least in the <template>
example at the top, that doesn't look like what would happen.)  It sounds
closer to a widget feature than a template.

I template HTML in HTML simply by sticking templates inside a hidden div
and cloning its contents into a DocumentFragment that I can insert wherever
I want.  The templates never contain scripts (unless I really mean for them
to be run at parse time).  I never nest templates this way, but there's
nothing preventing it.

It would be useful to have a <template> that works like that, which simply
gives me a "clone contents into DocumentFragment" function (basically
cloneNode(true), but returning a top-level element of DocumentFragment
instead of HTMLTemplateElement), and hints the browser that the contents
are a template (eg. it may want to deprioritize loading images within it).
It wouldn't be intended to hold script, and if you did put script blocks
inside them they'd just be run when parsed (since that's what browsers
today will do with it).  It requires no escaping at all, and parses like
any other tree, unlike the <script> approach which would just be an opaque
block of text, so you couldn't manipulate it in-place with DOM APIs and
it'd take a lot more work to make it viewable in developer tools, etc.

This would essentially be a CSS rule "template { display: none; }" and an
interface that gives a "cloneIntoFragment" (or something) method.

With the more complicated approaches people are suggesting I assume there
are use cases this doesn't cover--what are they?

-- 
Glenn Maynard
Received on Friday, 2 November 2012 21:16:58 GMT

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