Tags: hack



Saturday, January 16th, 2021

Enable/unmute WebAudio on iOS, even while mute switch is on

Remember when I wrote about Web Audio weirdness on iOS? Well, this is a nice little library that wraps up the same hacky solution that I ended up using.

It’s always gratifying when something you do—especially something that feels so hacky—turns out to be independently invented elsewhere.

Monday, December 21st, 2020

Web Audio API weirdness on iOS

I told you about how I’m using the Web Audio API on The Session to generate synthesised audio of each tune setting. I also said:

Except for some weirdness on iOS that I had to fix.

Here’s that weirdness…

Let me start by saying that this isn’t anything to do with requiring a user interaction (the Web Audio API insists on some kind of user interaction to prevent developers from having auto-playing sound on websites). All of my code related to the Web Audio API is inside a click event handler. This is a different kind of weirdness.

First of all, I noticed that if you pressed play on the audio player when your iOS device is on mute, then you don’t hear any audio. Seems logical, right? Except if using the same device, still set to mute, you press play on a video or audio element, the sound plays just fine. You can confirm this by going to Huffduffer and pressing play on any of the audio elements there, even when your iOS device is set on mute.

So it seems that iOS has different criteria for the Web Audio API than it does for audio or video. Except it isn’t quite that straightforward.

On some pages of The Session, as well as the audio player for tunes (using the Web Audio API) there are also embedded YouTube videos (using the video element). Press play on the audio player; no sound. Press play on the YouTube video; you get sound. Now go back to the audio player and suddenly you do get sound!

It’s almost like playing a video or audio element “kicks” the browser into realising it should be playing the sound from the Web Audio API too.

This was happening on iOS devices set to mute, but I was also getting reports of it happening on devices with the sound on. But it’s that annoyingly intermittent kind of bug that’s really hard to reproduce consistently. Sometimes the sound doesn’t play. Sometimes it does.

Following my theory that the browser needs a “kick” to get into the right frame of mind for the Web Audio API, I resorted to a messy little hack.

In the event handler for the audio player, I generate the “kick” by playing a second of silence using the JavaScript equivalent of the audio element:

var audio = new Audio('1-second-of-silence.mp3');

I’m not proud of that. It’s so hacky that I’ve even wrapped the code in some user-agent sniffing on the server, and I never do user-agent sniffing!

Still, if you ever find yourself getting weird but inconsistent behaviour on iOS using the Web Audio API, this nasty little hack could help.

Wednesday, December 16th, 2020


I spent the last couple of weekends rolling out a new feature on The Session. It involves playing audio in a web page. No big deal these days, right? But the history involves some old file formats…

The first venerable format is ABC notation. File extension: .abc, mime type: text/vnd.abc. It’s an ingenious text format for musical notation using ASCII. The metadata of the piece of music is defined in JSON-like key/value pairs. Then the contents are encoded with letters: A, B, C, etc. Uppercase and lowercase denote different octaves. Numbers can be used for note lengths.

The format was created by Chris Walshaw in 1997 when dial-up was the norm. With ABC, people were able to swap tunes on email lists or bulletin boards without transferring weighty image or sound files. If you had ABC software on your computer, you could convert that lightweight text file into sheet music …or audio.

That brings me to the second old format: midi files. File extension: .mid, mime-type: audio/midi. Like ABC, it’s a lightweight format for encoding the instructions for music instead of the music itself.

Think of it like SVG: instead of storing the final pixels of an image, SVG stores the instructions for drawing the image instead. The instructions in a midi file are like “play this note for this long on this instrument.” Again, as with ABC, you need some software to turn the instructions into sound.

There was a time when lots of software could play midi files. Quicktime on the Mac, for example. You could even embed midi files in web pages. I mean literally embed them …with the embed element. No Geocities page was complete without an autoplaying midi file.

On The Session, people submit tunes in ABC format. Then, using the amazing ABCJS JavaScript library, the ABC is turned into SVG on the fly! For years I’ve also offered midi files, generated on the server from the ABC notation.

But times have changed. These days it’s hard to find software that plays midi files. Quicktime doesn’t do it anymore. And you’d need to go to the app store on iOS to find a midi file player. It’s time to phase out the midi files on The Session.

I still want to provide automatically-generated audio though. Fortunately ABCJS gives me a way to do this. But instead of using the old technology of midi files, it uses a more modern browser feature: the Web Audio API.

The end result sounds like a midi file, but the underlying technique is more like a synthesiser. There’s a separate mp3 file for each note. The JavaScript figures out how long each “sample” needs to be played for, strings them all together, and outputs them with Web Audio. So you’ve got cutting-edge browser technology recreating a much older file format. Paul Rosen—the creator of ABCJS—has a presentation explaining how it all works under the hood.

Not only is there a separate short mp3 file for each note in seven octaves, but if you want the sound of a different instrument, you need samples for all seven octaves in that instrument. They’re called soundfonts.

Paul provides soundfonts for ABCJS. It’s a repo that was forked from this repo from Benjamin Gleitzman. And here’s where it gets small worldy…

The reason why Benjamin has a repo of soundfonts is because he needed to create midi-like audio in the browser. He wanted to do this for a project on September 28th and 29th, 2013 …at Science Hack Day San Francisco!

I was there too—working on my own audio-related hack—and I remember the excellent (and winning) hack that Benjamin worked on. It was called Symphony of Satellites and it’s still online along with the promo video. Here’s Benjamin’s post-hackday write-up from seven years ago.

It’s rare that the worlds of the web and Irish music cross over. When I got to meet Paul—creator of ABCJS—at a web conference a couple of years ago it kind of blew my mind. Last weekend when I set out to dabble with a feature on The Session, I certainly didn’t expect to stumble on a connection to Science Hack Day! (Aside: the first Science Hack Day was ten years ago—yowzers!)

Anyway, I was able to get that audio playback working on The Session. Except for some weirdness on iOS that I had to fix. But that’s a hack for another day.

Friday, August 28th, 2020

Revisiting Adaptive Design, a lost design movement (Interconnected)

This sounds like seamful design:

How to enable not users but adaptors? How can people move from using a product, to understanding how it hangs together and making their own changes? How do you design products with, metaphorically, screws not nails?

Tuesday, April 28th, 2020

Principles and priorities | Hacker News

I see that someone dropped one of my grenades into the toilet bowl of Hacker News.

Monday, February 3rd, 2020

Old CSS, new CSS / fuzzy notepad

I absolutely love this in-depth history of the web, written in a snappy, snarky tone.

In the beginning, there was no CSS.

This was very bad.

Even if you—like me—lived through all this stuff, I guarantee there’ll still be something in here you didn’t know.

Google Maps Hacks, Performance and Installation, 2020 By Simon Weckert

I can’t decide if this is industrial sabotage or political protest. Either way, I like it.

99 second hand smartphones are transported in a handcart to generate virtual traffic jam in Google Maps.Through this activity, it is possible to turn a green street red which has an impact in the physical world by navigating cars on another route to avoid being stuck in traffic

Tuesday, October 15th, 2019

Jeremy Keith & Remy Sharp - How We Built the World Wide Web in Five Days on Vimeo

Here’s the talk that Remy and I gave at Fronteers in Amsterdam, all about our hack week at CERN. We’re both really pleased with how this turned out and we’d love to give it again!

Monday, October 14th, 2019

Something for the weekend

Your weekends are valuable. Spend them wisely. I have some suggestion on how you might spend next weekend, October 19th and 20th, depending on where you are in the world.

If you’re in the bay area, or anywhere near San Francisco, I highly recommend that you go to Science Hack Day—two days of science, hacking, and fun. This will be the last one in San Francisco so don’t miss your chance.

If you’re in the south of England, or anywhere near Brighton, come along to Indie Web Camp. Saturday will feature discussions on owning your data. Sunday will be a day of doing. I’ve written about previous Indie Web Camps before, and I really can’t recommend it highly enough!

Do me a favour and register for a spot—it’s free—so I’ve got some idea of numbers. Looking forward to seeing you there!

Tuesday, May 28th, 2019

Opinion | It’s 2059, and the Rich Kids Are Still Winning - The New York Times

The New York Times is publishing science-fictional op-eds. The first one is from Ted Chiang on the Gene Equality Project forty years in our future:

White supremacist groups have claimed that its failure shows that certain races are incapable of being improved, given that many — although by no means all — of the beneficiaries of the project were people of color. Conspiracy theorists have accused the participating geneticists of malfeasance, claiming that they pursued a secret agenda to withhold genetic enhancements from the lower classes. But these explanations are unnecessary when one realizes the fundamental mistake underlying the Gene Equality Project: Cognitive enhancements are useful only when you live in a society that rewards ability, and the United States isn’t one.

Wednesday, May 22nd, 2019


Last week was a bit of an event whirlwind. In the space of seven days I was at Indie Web Camp, Beyond Tellerrand, and Accessibility Club in Düsseldorf, followed by a train ride to Utrecht for Frontend United. Phew!

Indie Web Camp Düsseldorf was—as always—excellent. Once again, Sipgate generously gave us the use of their lovely, lovely space for the weekend. We had one day of really thought-provoking discussions, followed by a day of heads-down hacking and making.

I decided it was time for me to finally own my replies. For a while now, I’ve been posting notes on my own site and syndicating to Twitter. But whenever I replied to someone else’s tweet, I did from Twitter. I wanted to change that.

From a coding point of view, it wasn’t all that tricky. The real challenges were to do with the interface. I needed to add another field for the URL I’m replying to …but I didn’t want my nice and minimal posting interface to get too cluttered. I ended up putting the new form field inside a details element with a summary of “Reply to” so that the form field would be hidden by default, and toggled open by hitting that “Reply to” text:

        <label for="replyto">Reply to</label>
    <input type="url" id="replyto" name="replyto">

I sent my first test reply to a post on Aaron’s website. Aaron was sitting next to me at the time.

Once that was all working, I sent my first reply to a tweet. It was a response to a tweet from Tantek. Tantek was also sitting next to me at the time.

I spent most of the day getting that Twitter syndication to work. I had something to demo, but I foolishly decided to risk it all by attempting to create a bookmarklet so that I could post directly from a tweet page (instead of hopping back to my own site in a different tab). By canabalising the existing bookmarklet I use for posting links, I just about managed to get it working in time for the end of day demos.

So I’m owning my replies now. At the moment, they show up in my home page feed just like any other notes I post. I’m not sure if I’ll keep it that way. They don’t make much sense out of context.

Then again, I kind of like how wonderfully random and out-of-context they look. You can browse through all my replies so far.

I’m glad I got this set up. Now when Andy posts stuff on Twitter, I’m custodian of my responses:

@AndyBudd: Who are your current “Design Heroes”?

adactio.com: I would say Falcor from Neverending Story, the big flying dog.

Sunday, May 12th, 2019

IndieWebCamp Düsseldorf 2019 | 2 | Flickr

Today was a good day …and here are the very good photos.


Wednesday, May 8th, 2019

CSS-only chat

A truly monstrous async web chat using no JS whatsoever on the frontend.

This is …I mean …yes, but …it …I …

Friday, March 29th, 2019

CERN Hack days – Chiteri’s Blog

Martin gives a personal history of his time at the two CERN hack projects …and also provides a short history of the universe.

Wednesday, March 20th, 2019

CSS custom properties in generated content

Cassie posted a neat tiny lesson that she’s written a reduced test case for.

Here’s the situation…

CSS custom properties are fantastic. You can drop them in just about anywhere that a property takes a value.

Here’s an example of defining a custom property for a length:

:root {
    --my-value: 1em;

Then I can use that anywhere I’d normally give something a length:

.my-element {
    margin-bottom: var(--my-value);

I went a bit overboard with custom properties on the new Patterns Day site. I used them for colour values, font stacks, and spacing. Design tokens, I guess. They really come into their own when you combine them with media queries: you can update the values of the custom properties based on screen size …without having to redefine where those properties are applied. Also, they can be updated via JavaScript so they make for a great common language between CSS and JavaScript: you can define where they’re used in your CSS and then update their values in JavaScript, perhaps in response to user interaction.

But there are a few places where you can’t use custom properties. You can’t, for example, use them as part of a media query. This won’t work:

@media all and (min-width: var(--my-value)) {

You also can’t use them in generated content if the value is a number. This won’t work:

:root {
    --number-value: 15;
.my-element::before {
    content: var(--number-value);

Fair enough. Generated content in CSS is kind of a strange beast. Eric delivered an entire hour-long talk at An Event Apart in Seattle on generated content.

But Cassie found a workaround if the value you want to put into that content property is numeric. The CSS counter value is a kind of generated content—the numbers that appear in front of ordered list items. And you can control the value of those numbers from CSS.

CSS counters work kind of like variables. You name them and assign values to them using the counter-reset property:

.my-element {
    counter-reset: mycounter 15;

You can then reference the value of mycounter in a content property using the counter value:

.my-element {
    content: counter(mycounter);

Cassie realised that even though you can’t pass in a custom property directly to generated content, you can pass in a custom property to the counter-reset property. So you can do this:

:root {
    --number-value: 15;
.my-element {
    counter-reset: mycounter var(--number-value);
    content: counter(mycounter);

In a roundabout way, this allows you to use a custom property for generated content!

I realise that the use cases are pretty narrow, but I can’t help but be impressed with the thinking behind this. Personally, I would’ve just read that generated content doesn’t accept custom properties and moved on. I would’ve given up quickly. But Cassie took a step back and found a creative pass-the-parcel solution to the problem.

I feel like this is a hack in the best sense of the word: a creatively improvised solution to a problem or limitation.

I was trying to display the numeric value stored in a CSS variable inside generated content… Turns out you can’t do that. But you can do this… codepen.io/cassie-codes/p… (not saying you should, but you could)

Wednesday, March 13th, 2019

First Web browser revived during hackathon - YouTube

This is the lovely little film about our WorldWideWeb hack project. It was shown yesterday at CERN during the Web@30 celebrations. That was quite a special moment.

First Web browser revived during hackathon

Thursday, February 28th, 2019

WorldWideWeb coverage

Remy’s keeping a list of hyperlinks to stories covering our recent hack week at CERN.

Friday, February 22nd, 2019

n-gate.com. we can’t both be right.

Hacker News is an echo chamber focusing on computer posturing and self-aggrandizement. It is run by Paul Graham’s investment fund and sociopath incubator, Y Combinator.

There’s never been any reason to visit Hacker News, but now you really don’t need to ever go there. This site posts a weekly roundup, complete with commentary that’s even more snarky than Hacker News.

Here’s a fairly typical summary of a fairly typical thread:

A programmer at a spamhouse is transported to a world where people are not judged by the color scheme of their Atom window, but by the character assessment and culture fit reports they write about potential new hires. Hackernews spends a lot of time discussing how to bullshit people like the author into hiring them. A few Hackernews struggle with the knowledge that there are people who contribute to business without involving Git. Furious debates about “title inflation” break out amongst people who type javascript into computers and straight-facedly refer to themselves as “engineers”.

Oh, and I love the “about” page.

nexus-project / nexus-browser · GitLab

Here’s the source code for the WorldWideWeb project we did at CERN.

Thursday, February 21st, 2019

Design sprint?

Our hack week at CERN to reproduce the WorldWideWeb browser was five days long. That’s also the length of a design sprint. So …was what we did a design sprint?

I’m going to say no.

On the surface, our project has all the hallmarks of a design sprint. A group of people who don’t normally work together were thrown into an instense week of problem-solving and building, culminating in a tangible testable output. But when you look closer, the journey itself was quite different. A design sprint is typical broken into five phases, each one mapped on to a day of work:

  1. Understand and Map
  2. Demos and Sketch
  3. Decide and Storyboard
  4. Prototype
  5. Test

Gathered at CERN, hunched over laptops.

There was certainly plenty of understanding, sketching, and prototyping involved in our hack week at CERN, but we knew going in what the output would be at the end of the week. That’s not the case with most design sprints: figuring out what you’re going to make is half the work. In our case, we knew what needed to be produced; we just had to figure out how. Our process looked more like this:

  1. Understand and Map
  2. Research and Sketch
  3. Build
  4. Build
  5. Build

Now you could say that it’s a kind of design sprint, but I think there’s value in reserving the term “design sprint” for the specific five-day process. As it is, there’s enough confusion between the term “sprint” in its agile sense and “design sprint”.