Earth Notes: On Website Technicals (2018/11)Updated 2019-04-22 12:01 GMT
2018/11/17: IMG alt Attribute
The IMG tags can now take an
alt attribute instead of
trying to derive text from the final part of the image name (though
that remains sufficient and easier in many cases). This especially
helps for older images to avoid renaming them. Also it makes
possible use of characters such as '/' and '-' otherwise unavailable
due to the nature of the automated text extraction.
Because the alt text is going to be passed around between shell and HTML and who-knows-what, anything that looks like a significant metacharacter to any of those is forbidden, especially quotes, '&', '<' and dollar signs.
2018/11/15: SVG and Dynamic Images
I've been having fun making the new IMG tag work with dynamically-generated images and with SVG images. (In neither case should resized copies be made.)
Also I have introduced a new
respW CCS class, identical
resp, except that the IMG-support code allows images
up to twice the target main container width on desktop. This works
for large display images that are allowed to spill into the margins.
2018/11/11: AMP Hero
I have just adjusted the hero-banner HTML generation to be AMP-compatible. I am also for now suppressing the optional table of contents for AMP, since it uses details/summary which AMP rejects.
Upshot: I now have a normal body page with a hero banner and body photo(s) that passes AMP validation. Even with the hero image inlined! Hurrah!
2018/11/10: More AMP
I am plodding on with making pages more AMP-compatible, in particular
dealing with common image use cases with EOU's new '
tag, which can be converted to something legal for AMP
amp-img). A helpful feature for the non-AMP pages
IMG allows automatic pre-rendering and use of
smaller versions of such images for non-desktop, and makes for some
extra visual and HTML uniformity.
There are plenty of cases where something is "lost in translation"
at the moment, such as
alt text not auto-extractable
from the image name. (There are also AMP-illegal inline styles in
various places, etc.)
I also don't have a working validator tool for macOS, which means that auto-generation of pages cross-platform isn't possible. Indeed I have opened a couple of issues with the AMP folk:
But I have today passed validation for a version of the 'about' page that contains an image. So I can be confident that auto-generated AMP versions of all the main pages should be possible.
(My current plan, if I put up an AMP page set, is to have any that can't be correctly auto-generated, eg because of some AMP-illegal tag, be redirected to the mobile (m.) page in the interim.)
link rel Best Practice
In an equiry about how to properly
link rel different page
variants (desktop, mobile, AMP) together,
(AMP project issue: how to put canonical for website and mobile site)
John M of Google said:
... In short, you link to the AMP page from your canonical, and you link back from the AMP page to the canonical. So to give an example, with separate mobile pages:https://www.example.com/desktop/page.html (this is the desktop version of the page) has: <link rel="alternate" media="only screen and (max-width: 640px)" href="https://m.example.com/mobile/page.html"> <link rel="amphtml" href="https://a.example.com/amp/page.html"> <link rel="canonical" href="https://www.example.com/desktop/page.html"> https://m.example.com/mobile/page.html (this is the smartphone version of the page) has: <link rel="canonical" href="https://www.example.com/desktop/page.html"> https://a.example.com/amp/page.html (this is the AMP version of the page) has: <link rel="canonical" href="https://www.example.com/desktop/page.html">
So the canonical page links out to all alternates, and the alternates need only link back to the canonical (ie not amongst one another).
In the case where the AMP version of a page cannot (currently) be generated
my current plan is to have it redirect (302?) to the m. page instead,
and probably not get an
alternate link from the desktop page.
2018/11/05: Mobile Hero Weight
Note to self:
I'm still aiming to keep mobile hero images <10kB to allow the
entire object to be immediately launched in flight on a new connection.
For that it has to be within the initial conjection window size
icwnd). Then there's no waiting for any ACKs and
their (horrible on cellular) RTTs.
2018/11/04: Shorter Path for Autogen Images
Auto-generated hero images were posted under
and later 'body' images under
Those paths have now been shortened to
img/a/b to reduce the HTML page size a tad,
maybe ~100 bytes from a typical .htmlgz (ZIP-compressed) page.