Tags: dom



Monday, September 19th, 2022

Wednesday, September 7th, 2022

“Writing an app is like coding for LaserDisc” – Terence Eden’s Blog

I love this: Terence takes eleven years to reflect on a comment I made on stage at an event here in Brighton. It’s all about the longevity of the web compared to native apps:

If you wrote an app for an early version of iOS or Android, it simply won’t run on modern hardware or software. APIs have changed, SDKs weren’t designed with forward compatibility, and app store requirements have evolved.

The web has none of that. The earliest websites are viewable on modern browsers.

As wrote at the time, I may have been juicing things up for entertainment:

Now here’s the thing when it comes to any discussion about mobile or the web or anything else of any complexity: an honest discussion would result in every single question being answered with “it depends”. A more entertaining discussion, on the other hand, would consist of deliberately polarised opinions. We went for the more entertaining discussion.

But I think this still holds true for me today:

The truth is that the whole “web vs. native” thing doesn’t interest me that much. I’m as interested in native iOS development as I am in native Windows development or native CD-ROM development. On a timescale measured in years, they are all fleeting, transient things. The web abides.

Wednesday, July 20th, 2022

Fandom Relics and the Enthusiastic Past - Long Now

Not much stays in one place for one long, especially when it comes to digital artifacts. When the Yahoo Groups archive was summarily deleted by parent company Verizon just a few years ago, fandom suffered massive losses, just as it had during the Livejournal purges of the late 02000s, and during the Tumblr porn ban in 02018. Fandom preservation, then, ties into the larger issue of digital preservation as a whole, and specifically the question of how individual and group emotions and experiences — which make up so much of what it means to be a fan — can be effectively documented, annotated, and saved.

Tuesday, April 12th, 2022

CSS Quick Tip: Animating in a newly added element | Stephanie Eckles

I can see myself almost certainly needing to use this clever technique at some point so I’m going to squirrel it away now for future me.

Monday, January 24th, 2022

Interfacecritique — Olia Lialina: From My To Me

Don’t see making your own web page as a nostalgia, don’t participate in creating the netstalgia trend. What you make is a statement, an act of emancipation. You make it to continue a 25-year-old tradition of liberation.

Thursday, July 22nd, 2021

Why Civilization Is Older Than We Thought – Palladium

When we find remains of beavers, we assume they built beaver dams, even if we don’t immediately find remnants of such dams. The beaver dams are part of what biologists would call the animal’s extended phenotype, an unavoidable necessity of the ecological niche that the beaver occupies. When we find Homo sapiens skeletons, however, we instead imagine the people naked, feasting on berries, without shelter, and without social differentiation.

Monday, July 5th, 2021

petite-vue - npm

An interesting alternative to using the full Vue library, courtesy of Vue’s creator:

petite-vue is an alternative distribution of Vue optimized for progressive enhancement. It provides the same template syntax and reactivity mental model with standard Vue. However, it is specifically optimized for “sprinkling” small amount of interactions on an existing HTML page rendered by a server framework.

Monday, March 22nd, 2021

1loc | Favorite JavaScript single line of code

This is very handy indeed! Quick one-line JavaScript helpers categorised by type.

And, no, you don’t need to npm install any of these. Try “vendoring” them instead (that’s copying and pasting to you and me).

Saturday, March 6th, 2021

Why I Still Use RSS | atthislink

Having only the content I want to see only be shown when I want to see it with the freedom to jump between readers as I please, all with no ads? For me, no other service comes close to the flexibility, robustness, and overall ease-of-use that RSS offers.

Thursday, November 19th, 2020


A graveyard for good domains you let expire.

Saturday, October 10th, 2020

Wednesday, August 26th, 2020

Submitting a form with datalist

I’m a big fan of HTML5’s datalist element and its elegant design. It’s a way to progressively enhance any input element into a combobox.

You use the list attribute on the input element to point to the ID of the associated datalist element.

<label for="homeworld">Your home planet</label>
<input type="text" name="homeworld" id="homeworld" list="planets">
<datalist id="planets">
 <option value="Mercury">
 <option value="Venus">
 <option value="Earth">
 <option value="Mars">
 <option value="Jupiter">
 <option value="Saturn">
 <option value="Uranus">
 <option value="Neptune">

It even works on input type="color", which is pretty cool!

The most common use case is as an autocomplete widget. That’s how I’m using it over on The Session, where the datalist is updated via Ajax every time the input is updated.

But let’s stick with a simple example, like the list of planets above. Suppose the user types “jup” …the datalist will show “Jupiter” as an option. The user can click on that option to automatically complete their input.

It would be handy if you could automatically submit the form when the user chooses a datalist option like this.

Well, tough luck.

The datalist element emits no events. There’s no way of telling if it has been clicked. This is something I’ve been trying to find a workaround for.

I got my hopes up when I read Amber’s excellent article about document.activeElement. But no, the focus stays on the input when the user clicks on an option in a datalist.

So if I can’t detect whether a datalist has been used, this best I can do is try to infer it. I know it’s not exactly the same thing, and it won’t be as reliable as true detection, but here’s my logic:

  • Keep track of the character count in the input element.
  • Every time the input is updated in any way, check the current character count against the last character count.
  • If the difference is greater than one, something interesting happened! Maybe the user pasted a value in …or maybe they used the datalist.
  • Loop through each of the options in the datalist.
  • If there’s an exact match with the current value of the input element, chances are the user chose that option from the datalist.
  • So submit the form!

Here’s how that translates into DOM scripting code:

document.querySelectorAll('input[list]').forEach( function (formfield) {
  var datalist = document.getElementById(formfield.getAttribute('list'));
  var lastlength = formfield.value.length;
  var checkInputValue = function (inputValue) {
    if (inputValue.length - lastlength > 1) {
      datalist.querySelectorAll('option').forEach( function (item) {
        if (item.value === inputValue) {
    lastlength = inputValue.length;
  formfield.addEventListener('input', function () {
  }, false);

I’ve made a gist with some added feature detection and mustard-cutting at the start. You should be able to drop it into just about any page that’s using datalist. It works even if the options in the datalist are dynamically updated, like the example on The Session.

It’s not foolproof. The inference relies on the difference between what was previously typed and what’s autocompleted to be more than one character. So in the planets example, if someone has type “Jupite” and then they choose “Jupiter” from the datalist, the form won’t automatically submit.

But still, I reckon it covers most common use cases. And like the datalist element itself, you can consider this functionality a progressive enhancement.

Saturday, August 1st, 2020

this vs that - What is the difference between ___ and ___ in the front-end development?

A handy reference for explaining the differences between confusingly similar bits of HTML, CSS, and JavaScript.

Sunday, July 19th, 2020

90s Festival Generator

I spent far too long hitting refresh and then clicking on the names of some of the Irish bands down near the bottom of the line-up.

Saturday, July 11th, 2020

A little bit of plain Javascript can do a lot

I decided to implement almost all of the UI by just adding & removing CSS classes, and using CSS transitions if I want to animate a transition.

Yup. It’s remarkable how much can be accomplished with that one DOM scripting pattern.

I was pretty surprised by how much I could get done with just plain JS. I ended up writing about 50 lines of JS to do everything I wanted to do.

Tuesday, July 7th, 2020

Custom properties

I made the website for the Clearleft podcast last week. The design is mostly lifted straight from the rest of the Clearleft website. The main difference is the masthead. If the browser window is wide enough, there’s a background image on the right hand side.

I mostly added that because I felt like the design was a bit imbalanced without something there. On the home page, it’s a picture of me. Kind of cheesy. But the image can be swapped out. On other pages, there are different photos. All it takes is a different class name on that masthead.

I thought about having the image be completely random (and I still might end up doing this). I’d need to use a bit of JavaScript to choose a class name at random from a list of possible values. Something like this:

var names = ['jeremy','katie','rich','helen','trys','chris'];
var name = names[Math.floor(Math.random() * names.length)];

(You could paste that into the dev tools console to see it in action on the podcast site.)

Then I read something completely unrelated. Cassie wrote a fantastic article on her site called Making lil’ me - part 1. In it, she describes how she made the mouse-triggered animation of her avatar in the footer of her home page.

It’s such a well-written technical article. She explains the logic of what she’s doing, and translates that logic into code. Then, after walking you through the native code, she shows how you could use the Greeksock library to achieve the same effect. That’s the way to do it! Instead of saying, “Here’s a library that will save you time—don’t worry about how it works!”, she’s saying “Here’s it works without a library; here’s how it works with a library; now you can make an informed choice about what to use.” It’s a very empowering approach.

Anyway, in the article, Cassie demonstrates how you can use custom properties as a bridge between JavaScript and CSS. JavaScript reads the mouse position and updates some custom properties accordingly. Those same custom properties are used in CSS for positioning. Voila! Now you’ve got the position of an element responding to mouse movements.

That’s what made me think of the code snippet I wrote above to update a class name from JavaScript. I automatically thought of updating a class name because, frankly, that’s how I’ve always done it. I’d say about 90% of the DOM scripting I’ve ever done involves toggling the presence of class values: accordions, fly-out menus, tool-tips, and other progressive disclosure patterns.

That’s fine. But really, I should try to avoid touching the DOM at all. It can have performance implications, possibly triggering unnecessary repaints and reflows.

Now with custom properties, there’s a direct line of communication between JavaScript and CSS. No need to use the HTML as a courier.

This made me realise that I need to be aware of automatically reaching for a solution just because that’s the way I’ve done something in the past. I should step back and think about the more efficient solutions that are possible now.

It also made me realise that “CSS variables” is a very limiting way of thinking about custom properties. The fact that they can be updated in real time—in CSS or JavaScript—makes them much more powerful than, say, Sass variables (which are more like constants).

But I too have been guilty of underselling them. I almost always refer to them as “CSS custom properties” …but a lot of their potential comes from the fact that they’re not confined to CSS. From now on, I’m going to try calling them custom properties, without any qualification.

We need more inclusive web performance metrics | Filament Group, Inc.

Good point. When we talk about perceived performance, the perception in question is almost always visual. We should think more inclusively than that.

Wednesday, June 17th, 2020

Where did the focus go? | Amber’s Website

Amber documents a very handy bit of DOM scripting when it comes to debugging focus management: document.activeElement.

Wednesday, May 13th, 2020


This micro libarary does DOM diffing in native JavaScript:

Reef is an anti-framework.

It does a lot less than the big guys like React and Vue. It doesn’t have a Virtual DOM. It doesn’t require you to learn a custom templating syntax. It doesn’t provide a bunch of custom methods.

Reef does just one thing: render UI.

Sunday, May 10th, 2020

Getting Started with the DOM

Here’s a short clear introduction to DOM scripting.