Journal tags: mode

7

sparkline

When service workers met framesets

Oh boy, do I have some obscure browser behaviour for you!

To set the scene…

I’ve been writing here in my online journal for almost twenty years. The official anniversary will be on September 30th. But this website has been even online longer than that, just in a very different form.

Here’s the first version of adactio.com.

Like a tour guide taking you around the ruins of some lost ancient civilisation, let me point out some interesting features:

  • Observe the .shtml file extension. That means it was once using Apache’s server-side includes, a simple way of repeating chunks of markup across pages. Scientists have been trying to reproduce the wisdom of the ancients using modern technology ever since.
  • See how the layout is 100vw and 100vh? Well, this was long before viewport units existed. In fact there is no CSS at all on that page. It’s one big table element with 100% width and 100% height.
  • So if there’s no CSS, where is the border-radius coming from? Let me introduce you to an old friend—the non-animated GIF. It’s got just enough transparency (though not proper alpha transparency) to fake rounded corners between two solid colours.
  • The management takes no responsibility for any trauma that might befall you if you view source. There you will uncover JavaScript from the dawn of time; ancient runic writing like if (navigator.appName == "Netscape")

Now if your constitution was able to withstand that, brace yourself for what happens when you click on either of the two links, deutsch or english.

You find yourself inside a frameset. You may also experience some disorienting “DHTML”—the marketing term given to any combination of JavaScript and positioning in the late ’90s.

Note that these are not iframes, they are frames. Different thing. You could create single page apps long before Ajax was a twinkle in Jesse James Garrett’s eye.

If you view source, you’ll see a React-like component system. Each frameset component contains frame components that are isolated from one another. They’re like web components. Each frame has its own (non-shadow) DOM. That’s because each frame is actually a separate web page. If you right-click on any of the frames, your browser should give the option to view the framed document in its own tab or window.

Now for the part where modern and ancient technologies collide…

If you’re looking at the frameset URL in Firefox or Safari, everything displays as it should in all its ancient glory. But if you’re looking in Google Chrome and you’ve visited adactio.com before, something very odd happens.

Each frame of the frameset displays my custom offline page. The only way that could be served up is through my service worker script. You can verify this by opening the framest URL in an incognito window—everything works fine when no service worker has been registered.

I have no idea why this is happening. My service worker logic is saying “if there’s a request for a web page, try fetching it from the network, otherwise look in the cache, otherwise show an offline page.” But if those page requests are initiated by a frame element, it goes straight to showing the offline page.

Is this a bug? Or perhaps this is the correct behaviour for some security reason? I have no idea.

I wonder if anyone has ever come across this before. It’s a very strange combination of factors:

  • a domain served over HTTPS,
  • that registers a service worker,
  • but also uses framesets and frames.

I could submit a bug report about this but I fear I would be laughed out of the bug tracker.

Still …the World Wide Web is remarkable for its backward compatibility. This behaviour is unusual because browser makers are at pains to support existing content and never break the web.

Technically a modern website (one that registers a service worker) shouldn’t be using deprecated technology like frames. But browsers still need to be able support those old technologies in order to render old websites.

This situation has only arisen because the same domain—adactio.com—is host to a modern website and a really old one.

Maybe Chrome is behaving strangely because I’ve built my online home on ancient burial ground.

Update: Both Remy and Jake did some debugging and found the issue…

It’s all to do with navigation preloads and the value of event.preloadResponse, which I believe is only supported in Chrome which would explain the differences between browsers.

According to this post by Jake:

event.preloadResponse is a promise that resolves with a response, if:

  • Navigation preload is enabled.
  • The request is a GET request.
  • The request is a navigation request (which browsers generate when they’re loading pages, including iframes).

Otherwise event.preloadResponse is still there, but it resolves with undefined.

Notice that iframes are mentioned, but not frames.

My code was assuming that if event.preloadRepsonse exists in my block of code for responding to page requests, then there’d be a response. But if the request was initiated from a frameset, it is a request for a page and event.preloadRepsonse does exist …but it’s undefined.

I’ve updated my code now to check this assumption (and fall back to fetch).

This may technically still be a bug though. Shouldn’t a page loaded from a frameset count as a navigation request?

SVGs in dark mode

I added a dark mode to my site last year. Since then I’ve been idly toying with the addition of a dark mode to The Session too.

As with this site, the key to adding a dark mode was switching to custom properties for color and background-color declarations. But my plans kept getting derailed by the sheet music on the site. The sheet music is delivered as SVG generated by ABCJS which hard-codes the colour in stroke and fill attributes:

fill="#000000" stroke="#000000"

When I was describing CSS recently I mentioned the high specifity of inline styles:

Whereas external CSS and embedded CSS don’t have any effect on specificity, inline styles are positively radioactive with specificity.

Given that harsh fact of life, I figured it would be nigh-on impossible to over-ride the colour of the sheetmusic. But then I realised I was an idiot.

The stroke and fill attributes in SVG are presentational but they aren’t inline styles. They’re attributes. They have no affect on specifity. I can easily over-ride them in an external style sheet.

In fact, if I had actually remembered what I wrote when I was adding a dark mode to adactio.com, I could’ve saved myself some time:

I have SVGs of sparklines on my homepage. The SVG has a hard-coded colour value in the stroke attribute of the path element that draws the sparkline. Fortunately, this can be over-ridden in the style sheet:

svg.activity-sparkline path {
  stroke: var(--text-color);
}

I was able to do something similar on The Session. I used the handy currentColor keyword in CSS so that the sheet music matched the colour of the text:

svg path {
  fill: currentColor;
}
svg path:not(stroke="none") {
  stroke: currentColor;
}

Et voila! I now had light-on-dark sheet music for The Session’s dark mode all wrapped up in a prefers-color-scheme: dark media query.

I pushed out out the new feature and started getting feedback. It could be best summarised as “Thanks. I hate it.”

It turns out that while people were perfectly fine with a dark mode that inverts the colours of text, it felt really weird and icky to do the same with sheet music.

On the one hand, this seems odd. After all, sheet music is a writing system like any other. If you’re fine with light text on a dark background, why doesn’t that hold for light sheet music on a dark background?

But on the other hand, sheet music is also like an image. And we don’t invert the colours of our images when we add a dark mode to our CSS.

With that in mind, I went back to the drawing board and this time treated the sheet music SVGs as being intrinsicly dark-on-light, rather than a stylistic choice. It meant a few more CSS rules, but I’m happy with the final result. You can see it in action by visiting a tune page and toggling your device’s “appearance” settings between light and dark.

If you’re a member of The Session, I also added a toggle switch to your member profile so you can choose dark or light mode regardless of your device settings.

Dark mode revisited

I added a dark mode to my website a while back. It was a fun thing to do during Indie Web Camp Amsterdam last year.

I tied the colour scheme to the operating system level. If you choose a dark mode in your OS, my website will adjust automatically thanks to the prefers-color-scheme: dark media query.

But I’ve seen notes from a few friends, not about my site specifically, but about how they like having an explicit toggle for dark mode (as well as the media query). Whenever I read those remarks, I’d think “I’m really not sure I’ve got time to deal with adding that kind of toggle to my site.”

But then I realised, “Jeremy, you absolute muffin! You’ve had a theme switcher on your website for almost two decades now!”

Doh! I had forgotten about that theme switcher. It dates back to the early days of CSS. I wanted my site to be a demonstration of how you could apply different styles to the same underlying markup (this was before the CSS Zen Garden came along). Those themes are very dated now, but if you like you can view my site with a Zeldman theme or a sci-fi theme.

To offer a dark-mode theme for my site, all I had to do was take the default stylesheet, pull out the custom properties from the prefers-color-scheme: dark media query, and done. It took less than five minutes.

So if you want to view my site in dark mode, it’s one of the options in the “Customise” dropdown on every page of the website.

Dark mode

I had a very productive time at Indie Web Camp Amsterdam. The format really lends itself to getting the most of a weekend—one day of discussions followed by one day of hands-on making and doing. You should definitely come along to Indie Web Camp Brighton on October 19th and 20th to experience it for yourself.

By the end of the “doing” day, I had something fun to demo—a dark mode for my website.

Y’know, when I first heard about Apple adding dark mode to their OS—and also to CSS—I thought, “Oh, great, Apple are making shit up again!” But then I realised that, like user style sheets, this is one more reminder to designers and developers that they don’t get the last word—users do.

Applying the dark mode styles is pretty straightforward in theory. You put the styles inside this media query:

@media (prefers-color-scheme: dark) {
...
}

Rather than over-riding every instance of a colour in my style sheet, I decided I’d do a little bit of refactoring first and switch to using CSS custom properties (or variables, if you will).

:root {
  --background-color: #fff;
  --text-color: #333;
  --link-color: #b52;
}
body {
  background-color: var(--background-color);
  color: var(--text-color);
}
a {
  color: var(--link-color);
}

Then I can over-ride the custom properties without having to touch the already-declared styles:

@media (prefers-color-scheme: dark) {
  :root {
    --background-color: #111416
    --text-color: #ccc;
    --link-color: #f96;
  }
}

All in all, I have about a dozen custom properties for colours—variations for text, backgrounds, and interface elements like links and buttons.

By using custom properties and the prefers-color-scheme media query, I was 90% of the way there. But the devil is in the details.

I have SVGs of sparklines on my homepage. The SVG has a hard-coded colour value in the stroke attribute of the path element that draws the sparkline. Fortunately, this can be over-ridden in the style sheet:

svg.activity-sparkline path {
  stroke: var(--text-color);
}

The real challenge came with the images I use in the headers of my pages. They’re JPEGs with white corners on one side and white gradients on the other.

header images

I could make them PNGs to get transparency, but the file size would shoot up—they’re photographic images (with a little bit of scan-line treatment) so JPEGs (or WEBPs) are the better format. Then I realised I could use CSS to recreate the two effects:

  1. For the cut-out triangle in the top corner, there’s clip-path.
  2. For the gradient, there’s …gradients!
background-image: linear-gradient(
  to right,
  transparent 50%,
  var(—background-color) 100%
);

Oh, and I noticed that when I applied the clip-path for the corners, it had no effect in Safari. It turns out that after half a decade of support, it still only exists with -webkit prefix. That’s just ridiculous. At this point we should be burning vendor prefixes with fire. I can’t believe that Apple still ships standardised CSS properties that only work with a prefix.

In order to apply the CSS clip-path and gradient, I needed to save out the images again, this time without the effects baked in. I found the original Photoshop file I used to export the images. But I don’t have a copy of Photoshop any more. I haven’t had a copy of Photoshop since Adobe switched to their Mafia model of pricing. A quick bit of searching turned up Photopea, which is pretty much an entire recreation of Photoshop in the browser. I was able to open my old PSD file and re-export my images.

LEGO clone trooper Brighton bandstand Scaffolding Tokyo Florence

Let’s just take a moment here to pause and reflect on the fact that we can now use CSS to create all sorts of effects that previously required a graphic design tool like Photoshop. I could probably do those raster scan lines with CSS if I were smart enough.

dark mode

This is what I demo’d at the end of Indie Web Camp Amsterdam, and I was pleased with the results. But fate had an extra bit of good timing in store for me.

The very next day at the View Source conference, Melanie Richards gave a fantastic talk called The Tailored Web: Effectively Honoring Visual Preferences (seriously, conference organisers, you want this talk on your line-up). It was packed with great insights and advice on impementing dark mode, like this little gem for adjusting images:

@media (prefers-color-scheme: dark) {
  img {
    filter: brightness(.8) contrast(1.2);
  }
}

Melanie also pointed out that you can indicate the presence of dark mode styles to browsers, although the mechanism is yet to shake out. You can do it in CSS:

:root {
  color-scheme: light dark;
}

But you can also do it in HTML:

That allows browsers to swap out replaced content; interface elements like form fields and dropdowns.

Oh, and one other addition I added after the fact was swapping out map imagery by using the picture element to point to darker map tiles:

<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://api.mapbox.com/styles/v1/mapbox/dark-v10/static...">
<img src="https://api.mapbox.com/styles/v1/mapbox/outdoors-v10/static..." alt="map">
</picture>

light map dark map

So now I’ve got a dark mode for my website. Admittedly, it’s for just one of the eight style sheets. I’ve decided that, while I’ll update my default styles at every opportunity, I’m going to preservethe other skins as they are, like the historical museum pieces they are.

If you’re on the latest version of iOS, go ahead and toggle the light and dark options in your system preferences to flip between this site’s colour schemes.

Amsterdam Brighton Amsterdam

I’m about to have a crazy few days that will see me bouncing between Brighton and Amsterdam.

It starts tomorrow. I’m flying to Amsterdam in the morning and speaking at this Icons event in the afternoon about digital preservation and long-term thinking.

Then, the next morning, I’ll be opening up the inaugural HTML Special which is a new addition the CSS Day conference. Each talk on Thursday will cover one HTML element. I am honoured to speaking about the A element. Here’s the talk description:

The world exploded into a whirling network of kinships, where everything pointed to everything else, everything explained everything else…

Enquire within upon everything.

I’ve been working all out to get this talk done and I finally wrapped it up today. Right now, I feel pretty happy with it, but I bet I’ll change that opinion in the next 48 hours. I’m pretty sure that this will be one of those talks that people will either love or hate, kind of like my 2008 dConstruct talk, The System Of The World.

After CSS Day, I’ll be heading back to Brighton on Saturday, June 18th to play a Salter Cane gig in The Greys pub. If you’re around, you should definitely come along—not only is it free, but there will be some excellent support courtesy of Jon London, and Lucas and King.

Then, the next morning, I’ll be speaking at DrupalCamp Brighton, opening up day two of the event. I won’t be able to stick around long afterwards though, because I need to skidaddle to the airport to go back to Amsterdam!

Google are having their Progressive Web App Dev Summit there on Monday on Tuesday. I’ll be moderating a panel on the second day, so I’ll need to pay close attention to all the talks. I’ll be grilling representatives from Google, Samsung, Opera, Microsoft, and Mozilla. Considering my recent rants about some very bad decisions on the part of Google’s Chrome team, it’s very brave of them to ask me to be there, much less moderate a panel in public.

You can still register for the event, by the way. Like the Salter Cane gig, it’s free. But if you can’t make it along, I’d still like to know what you think I should be asking the panelists about.

Got a burning question for browser/device makers? Write it down, post it somewhere on the web with a link back to this post, and then send me a web mention (there’s a form for you to paste in the URL at the bottom of this post).

Moderating EnhanceConf 2016

Last year I met up with Simon McManus in a Brighton pub where he told me about his plan to run a conference dedicated to progressive enhancement. “Sounds like a great idea!”, I said, and offered him any help I could.

With the experience of organising three dConstructs and three Responsive Days Out, I was able to offer some advice on the practical side of things like curation, costs and considerations. Simon also asked me to MC his event. I was only too happy to oblige. After all, I was definitely going to be at the conference—wild horses wouldn’t keep me away—and when have I ever turned down an opportunity to hog the mic?

Simon chose a name: EnhanceConf. He found a venue: The RSA in London. He settled on a date: March 4th, 2016. He also decided on a format, the same one as Responsive Day Out: four blocks of talks, each block consisting of three back-to-back 20 minute presentations followed by a group discussion and questions.

With all those pieces in place, it was time to put together a line-up. I weighed in with my advice and opinions there too, but the final result was all Simon’s …and what a great result it was.

Yesterday was the big day. I’m happy to report that it was a most splendid event: an inspiring collection of brilliant talks, expertly curated like a mixtape for the web.

Nat got the day off to a rousing start. They gave an overview of just how fragile and unpredictable the World Wide Web can be. To emphasise this, Anna followed with detailed look at the many, many console browsers people are using. Then Stefan gave us a high-level view of sensible (and not-so-sensible) architectures for building on the web—a talk packed to the brim with ideas and connections to lessons from the past that really resonated with me.

Stefan, Nat and Anna

After that high-level view, the next section was a deep dive into strategies for building with progressive enhancement: building React apps that share code for rendering on the server and the client from Forbes; using Service Workers to create a delightful offline experience from Olly; taking a modular approach to how structure our code and cut the mustard from Stu.

Stu, Olly and Forbes

The after-lunch session was devoted to design. It started with good ol’ smackdown between Phil and Stephen, which I attempted to introduce in my best wrestling announcer voice. That was followed by a wonderfully thoughtful presentation by Adam Silver on Embracing Simplicity. Then Jen blew everyone away with a packed presentation of not just what’s possible with CSS now, but strategies for using the latest and greatest CSS today.

Adam, Stephen, Phil and Jen

Finally, the day finished with a look to the future. And the future is …words. Robin was as brilliant as ever, devising an exercise to get the audience to understand just how awful audio CAPTCHAs are, but also conveying his enthusiasm and optimism for voice interfaces. That segued perfectly into the next two talks. Stephanie gave us a crash course in crafting clear, concise copy, and Aaron tied that together with Robin’s musings on future interactions with voice in a great final presentation called Learn From the Past, Enhance for the Future (echoing the cyclical patterns that Stefan was talking about at the start of the day).

Closing panel

As the day wrapped up, I finished by pointing to a new site launched by Jamie on the very same day: progressiveenhancement.org. With that, my duties were fulfilled.

I thoroughly enjoyed listening to the talks and then quizzing the speakers afterwards. I really do enjoy moderating events. Some of the skills are basic (pronouncing people’s names correctly, using their preferred pronouns) and some are a little trickier (trying to quickly spot connections, turning those connections into questions for each speaker) but it’s very rewarding indeed.

I had a blast at EnhanceConf. I felt bad though; lots of people came up to me and started thanking me for a great day. “Don’t thank me!” I said, “Thank Simon.”

Thanks, Simon.

CERN and the line-mode browser

I remember when Mark took me aside to tell me about the project he was working on with CERN to restore the first ever website to its original URL. Needless to say, I was extremely pleased. After all, cool URIs don’t change.

Then, more recently, Mark told me about a follow-up project they were planning: to recreate the experience of using one of the first web browsers. He asked if I could help organise a hackday-style gathering to accomplish this. I jumped at the chance.

Together with Dan Noyes from the web team at CERN, we assembled a dozen people. Half of them were invited experts and half were chosen from applications. Because I was ostensibly involved in organising the event (although I didn’t really do much), I got a free pass.

And so we gathered in a war-room at CERN on the 18th and 19th of September to hack away at recreating the experience of using the line-mode browser in a modern browser—browserception!

Hacking

Just to be clear, the line-mode browser wasn’t the world’s first web browser. That honour goes to Tim Berners-Lee’s WorldWideWeb programme. But whereas WorldWideWeb only ran on NeXT machines, the line-mode browser worked cross-platform and was, therefore, instrumental in demonstrating the power of the web as a universally-accessible medium.

Just being at CERN was amazing. It’s like double Disneyland for me: not only is it home to the greatest experiment conducted in the history of our species, it’s also the birthplace of the web itself. We all felt quite humbled to be there.

That feeling was amplified when we had a very special guest show up at the start of the event—Robert Cailliau, co-conspirator with Tim Berners-Lee in getting the web off the ground. He gave us a history lesson in the early days of the web; the ideas, the people, and the principles that drove it. At one point, he passed around his notarised copy of the document that put the web into the public domain twenty years ago. “Be careful with that,” he half-joked. “CERN don’t know where their copy is anymore.”

Robert

We had another guest from the early days of the web with us for the duration of our hacking: an IBM RS/6000 machine from the early nineties running the line-mode browser.

Jeremy Brian

I drew on my experience from hack farm and Science Hack Day to get the ball rolling. I was acutely aware that some of us felt pretty unsure about what we could contribute, so I suggested splitting into two teams: one to work on building the line-mode browser simulator, and the other to work on telling the story of its history. That seemed to work out pretty well.

Geeking out Planning Prepping Geeking out

Remy and Brian L. did the really hard work, implementing a simulation of the line-mode browser in Node.js. Lea, Kimberly and John made sure the output looked and felt right. Meanwhile Brian S. had the crazy idea of trying to recreate the font from the IBM machine …by taking a photo of the screen and drawing the glyphs from the photo! Of course Mark jumped on that.

Craig headed up the story-telling side of things with Martin and Angela. My contribution consisted of writing some explanatory words and doing a bit of image optimisation. It would be easy to feel inadequate in the company of such talented developers, but as the hacking went on, it was clear that all those little contributions really add up.

We made a thing

It will probably move from its current URL—line-mode.cern.ch—to a permanent home. In the meantime, why not grab the code and install a copy locally?

  1. Install Node.js.
  2. Clone the github repo to your machine.
  3. Open up the Terminal, navigate to your cloned copy, and type: node .
  4. Open localhost:8000 in a browser.

You can read more about the project but I’m guessing what you’ll really want to do is fire up the line-mode browser. By default it loads a copy of the first ever web page, but you can also navigate other websites by changing this query string:

line-mode.cern.ch/www/proxy?url=http://adactio.com

Or, if you’re running it locally:

localhost:8000/www/proxy?url=http://adactio.com

You can also grab a bookmarklet from the resources page. Drag it to your bookmarks bar, pull up whatever page you want to view, and hit the bookmarklet to see it line-mode style.

dConstruct Huffduffer Adactio Clearleft

All the little details—the font, the animation, the sound—add up to an experience that I find quite immersive. In some ways, it’s a silly little project, but it’s also trying to convey an important message. I really love the final result. I feel incredibly honoured to have been involved—in a small way—in its creation.

Oh, and we also got to go down into the heart of the Large Hadron Collider to see the LHCb experiment. That was, in the truest sense of the word, awesome.

Dan LHCb Amongst the machines LHCb