CSS now has an if() conditional function

https://caniuse.com/?search=if

by aanthonymax • 8 months ago

272 228 8 months ago

caniuse.com

aanthonymax• 8 months ago

This support has appeared in the new W3C specification.

tantalor• 8 months ago

https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...

themafia• 8 months ago

It's a great way to make conditional styles without having to use JavaScript; however, having used JS for years to make theme color and icon sets that rely on CSS properties, I'm not sure I particularly like this method. I feel like you have to smear a lot of logic across your CSS whereas with JS you can reduce your theme to a data structure and just have a simple function to setup all the CSS variables based on that.

Am I just an old man?

kevin_thibedeau• 8 months ago

Just use SCSS to smear the logic across CSS automatically.

functionmouse• 8 months ago

I like making static informational pages and don't know the first thing about JavaScript, so this could be handy for me.

mmis10003• 8 months ago

Javascript always suffer from FOUC problem though (Unless it's server side). Although the if() css function seems to just be syntax suger of standard @media query. So it doesn't really add anything to solve existing problems.

Edited: It seems it can also be toggled from css variable? So it might actually fix some existing problems.

mikestorrent• 8 months ago

How hard would it be to have a response header that tells the browser "don't display anything at all until we ask you to from JS when we're ready"?

Considering the kinds of crap that have been done with headers...

bawolff4• 8 months ago

The primary goal is to just have a more concise way to do @media queries. Its not intended as a replacement for most uses of JS

6031769• 8 months ago

If we've learned anything from the history of CSS, JS and the semantic web it is that 99% of the time a feature will be used in ways that were not intended. There is no reason to suppose that this will be any different.

Denote6737• 8 months ago

God forbid we use html5

assimpleaspossi• 8 months ago

There is no HTML5 other than a buzzword: https://html.spec.whatwg.org/dev/introduction.html#is-this-h...?

pie_flavor• 8 months ago

You're pulling the old man card on CSS-in-JS? Putting your style logic in CSS is what CSS is for, CSS-in-JS is an annoying hack to make React work. What this is replacing is SCSS.

masswerk• 8 months ago

Well, historically, styles were first in JS (JS StyleSheets in Netscape 4.0) and were pulled out into CSS. – This is an old man card! ;-)

stevefan1999• 8 months ago

With the inclusion of branches, is it possible to say that CSS is now even more Turing-Complete? Now we just need to find ways to do recursion/targeted jumps so that it is finally recursive-enumerable

ImHereToVote• 8 months ago

Doom on CSS when?

anthk3• 8 months ago

You can maybe run ZMachine games (not just Zork, there are several better games there) under zmachine.ps, written in PostScript.

And, maybe, in a TTF font.

cluckindan3• 8 months ago

Don’t apply programming language mental models onto CSS features.

CSS if() probably just merges one of two single-property RuleSets onto the parent RuleSet depending on the condition, which has nothing to do with branching, as there is no execution flow to branch.

culi3• 8 months ago

Far from being ready when only one major browser supports it. If you want this, you should vote for it to be focused on for interop-2026

https://github.com/web-platform-tests/interop/issues

Right now, the leading CSS proposals are `@container style()`, `corner-shape` and `break-after`

https://foolip.github.io/interop-reactions/

hdjrudni• 8 months ago

Yeesh.. I've definitely tried using break-after and being disappointed it didn't work properly. The amount of hoops I had to jump through to get things to print properly on paper...

fuzzfactor2• 8 months ago

The amount of hoops I had to jump through to get things to print properly on paper...

Anybody know how that compares to Report Definition Language?

https://learn.microsoft.com/en-us/sql/reporting-services/rep...

Seems like an awfully scattered shitshow just to arrive at a typical "What You See Is Not What You Get" result.

And this one is made for printouts.

culi3• 8 months ago

Agreed. This has come up multiple times during my job. It's gotten to the point where we had a microservice running that spun up selenium and printed the dom and then sent that pdf back to the front-end all just to make consistent print outputs. I've read tech blogs of others doing just that too so it's not uncommon.

Unfortunately the test set of wpt does not have the capability to cover printed matter so relief isn't coming any time soon

StoneAndSky• 8 months ago

The People have spoken, and they want squircles.

zb3• 8 months ago

Not supported in Firefox and Safari. Also it seems most people forget that the more bloated the web platform is, the more resources are needed to develop and maintain a web browser engine.. Chromium is open-source, but it's already expensive to maintain a fork or even rebuild it..

lenkite3• 8 months ago

They just need to start deprecating and removing old features. They had no issues with XSLT removal even when some major sites like the library of congress used it. So the excuse of backward compatability has already proven to be a lie.

tgv• 8 months ago

Yeah. Font-size and width, be gone!

alwillis4• 8 months ago

They just need to start deprecating and removing old features.

That's not going to happen.

They can't break millions of websites by removing old features. Besides, for the most part, current developers can ignore most of the old stuff.

But a site made in 1997 has to render on current browsers.

xnx• 8 months ago

If we could do it over, knowing that we'd eventually get to this point, would https://en.wikipedia.org/wiki/JavaScript_Style_Sheets have been the better path?

runarberg5• 8 months ago

Probably not. There is a lot of optimizations browsers do to make the stylesheets super fast[1], and I think quite a few of those rely on CSS not being Turing complete.

1: https://hacks.mozilla.org/2017/08/inside-a-super-fast-css-en...

Sesse__4• 8 months ago

CSS is Turing complete :-) You can find pure-CSS implementations of Game of Life, for instance.

inopinatus• 8 months ago

If I had a time machine I would go back and ensure that DSSSL (https://en.wikipedia.org/wiki/Document_Style_Semantics_and_S...) was the standard that got up.

runarberg5• 8 months ago

You write your markup in an xml syntax, your scripts in a C syntax, and your styles in a lisp syntax... a perfect trio.

watersb• 8 months ago

All hail the embedded Scheme interpreter to apply Style transformations!

Although I feel like we've already explored this with XSL. The XML syntax was perhaps too much to swallow.

bawolff4• 8 months ago

I would say no. I think CSS is a good language and made good choices.

And honestly we already essentially have this with CSS related apis in js. The examples in that article are basically identical to how you set css in js on modern web browsers with slightly different naming conventions.

shiomiru• 8 months ago

I actually wonder if transpiling calc/min/max/etc. expressions to JS is a viable path to implementation, considering that you already need a fast interpreter for these.

rcarmo2• 8 months ago

Knowing what we know, we would probably have stepped out of our time machine to make sure that Brendan Eich kept the Scheme-based syntax and added semantic HTML enrichment for styling, sparing untold grief over the last generation...

BrendanEich• 7 months ago

I don't know what "semantic HTML enrichment" means, but there wasn't time. The alternative was VBScript and DHTML. DHTML and Netscape's DOM forked Web content based on `if (document.all) /* IE code here */; else /* netscape code here */`, and only with Firefox, Opera, and Safari founding whatwg.org and start HTML5 did we unify everything.

cestith2• 8 months ago

If we could do over, web browsers should have supported two document formats from the beginning - HTML for plain text markup and the preexisting Turing-complete formatting language of either PostScript or encapsulated PostScript.

mr_windfrog• 8 months ago

I'm not really sure I understand this. How is the new if() conditional function different from using @media (width ...) when adapting layouts to browser width?

bawolff4• 8 months ago

Its basically the same, just more convinent syntax.

I think if can also do string equality on variable values, which is a bit new but also niche. The main point is just to do @media but inside a property decleration.

michaelcampbell• 8 months ago

If I'm reading it right, the if condition/predicate can check more things than @media() can.

bingemaker• 8 months ago

I'm not sure turning CSS into a full blown language is a good idea. With all the cascading in place, it is already a bit hard to determine why certain styles are applied. Now with this, we will be spending more brain cells debugging CSS issues.

lmm2• 8 months ago

On the contrary, a lot of the reason CSS is confusing is because it's full of insane hacks people have to do to get the behaviour they want. A straight-up if statement is much simpler than many of the horrors I've seen.

alwillis4• 8 months ago

On the contrary, a lot of the reason CSS is confusing is because it's full of insane hacks people have to do to get the behaviour they want.

CSS is confusing because the vast majority of web developers never learned it properly. Many developers won't learn any "new" CSS (like CSS Grid which shipped in all browsers in 2017) beyond the hacks they learned in the '90s and early 2000's.

That's not the fault of CSS.

adgjlsfhk1• 8 months ago

css definitely shouldn't have backwards branches (loops/recursive functions), but adding a little more power can clean up expression a ton and make reading/applying that much faster

lenkite3• 8 months ago

I wish the "little more power" would add CSS modules. It would also be great if web components didn't require Javascript and could be configured with pure HTML and CSS.

I will kiss the feet of the whatwg groups if they do this.

PS: Would also love to have declarative template inclusion now that removal of XSLT has also removed this facility from the browser.

silverwind• 8 months ago

This is missing a "if variable equals" imho. Right now it seems like pure syntactic sugar for a media query.

ramesh31• 8 months ago

This is missing a "if variable equals" imho.

This is exactly what it does not need. SASS style conditional CSS is a complete nightmare to maintain. The declarative nature is one of its greatest strengths.

bawolff4• 8 months ago

Did you guys read the docs? It literally does have this albeit the syntax is a bit odd:

if(style(--foo: bar): baz)

Is how you test if variable --foo is equal to "bar"

See https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...

foreigner• 8 months ago

Can these be used inside inline style attributes?

zuhsetaqi• 8 months ago

It's a working draft and only available in Chromium ...

zkmon2• 8 months ago

Give it enough time, every declarative language becomes a programming language. This is happening with all config files, markup languages, data formats.

The distinction between code, config and data is being erased. Everything is a soup now. Data is application, configuration is code. Code is an intermediate, volatile thing that is generated on the fly and executed in the temporary lambda containers.

thwarted2• 8 months ago

We can blame von Neumann (et al) and his infernal architecture, where memory stores both instructions and data.

account422• 8 months ago

Not really, most of these configuration as code systems are not executed directly on the CPU but rather interpreted in which case a separate data-only memory would not stop anyone.

josefx• 8 months ago

You can blame whoever invented the word "if", as soon as you can branch based on data you can just write an interpreter that turns data into instructions, no matter the architecture.

tovej• 8 months ago

von Neumann did not invent the von Neumann architecture. Not even a little bit.

If you want to reason that the hardware is at fault, you should be blaming the Eckert-Mauchley architecture.

pragma_x2• 8 months ago

FWIW, you can make software that runs on Harvard architecture chips. They feature distinct address spaces for ROM and RAM. It's been a while, but it's how Atmel/Microchip AVR micros work.

https://en.wikipedia.org/wiki/Harvard_architecture

That said, I'm unaware of any programming language (outside assembler) that takes that split to heart in a higher-level way.

john61• 8 months ago

The distinction between code, config and data is being erased.

This distinction never existed in LISP. Greenspun's tenth rule in action.

Galanwe• 8 months ago

This is so true, I have seen it happen with so many projects. It always starts with a cute declarative DSL, and inevitably imperative / flow control structures emerge, at which point you wonder why they didn't use a real programming language in the first place and save you the hassle or learning a half baked imperative DSL.

- Puppet

- CMake

- Terraform

- ...

All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.

Derbasti• 8 months ago

- Visual Studio project files are XML files that are interpreted line by line, and can contain variables, branches, and loops. Hell on earth.

spooky_deep5• 8 months ago

CMake was never declarative AFAIK?

CMake today is effectively an eso-lang / Turing tarpit with some “modern” declarative conventions that people try to push.

embedding-shape10• 8 months ago

All these started with pure declarative DSL then incrementally created a nightmarish imperative monstrosity.

"Huh?" I asked myself when you mentioned that Terraform is now imperative somehow. Took a look at the website again, and seems to still be HCL, and still be declarative. Am I missing something? How exactly is Terraform today a "imperative monstrosity"?

shevy-java5• 8 months ago

I think cmake kind of needs conditional checks though.

speed_spread2• 8 months ago

People love to hate on Maven's XML but at least it's been mostly the same since 2006. There are conditionals in profile activation expressions but they are very limited by design. Declarative done right, IMO

butlike2• 8 months ago

What's the old adage? Software expands until it can send email?

psychoslave2• 8 months ago

One reason I still love Ruby so much. It gives ability to easily define a DSL within a larger robust fully fledged language, and you can always tap on the larger ecosystem if needs evolve. This is a sharp contrast with starting something small from scratch (which might seems fine at the start), and later be on your own to scale things up as needs grow.

mseepgood• 8 months ago

So why do people still design declarative languages?

lionkor• 8 months ago

Wishful thinking? Maybe they are tired of all this and want to make something good again, and so the cycle continues.

noelwelsh• 8 months ago

OP is not being very precise (and in a way that I don't think is helpful). There is nothing imperative in an if expression. Declarative languages can be Turing complete. Declarative languages are a subset of programming languages.

xienze• 8 months ago

It’s the cycle of newcomers to <field> looking at the existing solutions and declaring “this shit is too complicated, why did these morons design it this way? Check out my DSL that does everything and is super simple!”

Then time passes, edge cases start cropping up and hacks are bolted on to accommodate them. Eventually everything struggles under the weight of not having loops, conditionals, etc. and those are added.

After some time, the cycle begins anew.

ahartmetz2• 8 months ago

If you can mostly stick to the declarative way, it's still a benefit. No Turing-complete language completely prevents you from writing "bad" code. "You are not completely prevented from doing things that are hard to understand" is a bad argument. "You are encouraged to do things that are hard to understand" is a good one (looking at you, Perl).

halfcat• 8 months ago

So why do people still design declarative languages?

Cost.

If money were no object, you would only hire people who can troubleshoot the entire stack, from React and SQL all the way down to machine code and using an oscilloscope to test network and power cabling.

Or put another way, it would be nice for the employer if your data analyst who knows SQL also knew C and how to compile Postgres from scratch, so they could fully debug why their query doesn’t do what they expect. But that’s a more expensive luxury.

Good software has declarative and imperative parts. It’s an eternal tradeoff whether you want the convenience of those parts being in the same codebase, which makes it easier to troubleshoot more of the stack, but that leads to hacks that break the separation. So sometimes you want a firm boundary, so people don’t do workarounds, and because then you can hire cheaper people who only need to know SQL or React or CSS or whatever, instead of all of them.

lucideer• 8 months ago

You have to give it to CSS, it's held out for a lot longer than most.

rebane2001• 8 months ago

not as much as you would think, the if statements don't really affect the css crimes scene because pretty much everything was already possible before

noosphr• 8 months ago

Those who don't use lisp are destined to re-invent it - poorly.

skywhopper• 8 months ago

“Now”? This has always been the case.

qouteall• 8 months ago

Configuration complexity clock

https://mikehadlow.blogspot.com/2012/05/configuration-comple...

zarzavat2• 8 months ago

Conditional expressions are declarative. For example, every template language worth its salt has conditionals.

A programming (i.e Turing complete) language requires recursion or a construct of equal power.

Starman_Jones• 8 months ago

There is no recursive program that can't also be created by adding in more conditionals. It's turtles the whole way down.

pjmlp6• 8 months ago

Unfortunely too many people are afraid of opening parentheses being posited on the far left instead of the middle of the text.

embedding-shape10• 8 months ago

It was shocking the first time I showed a lisp program to a (particularly "annoyed by everything") non-lisp developer who never apparently saw s-expressions before. Lots of knee-jerk reactions of "Oh my god so many parenthesis" and "How could anyone program like this?" while they sat there smug with their TypeScript codebase having more special characters, syntax and the same amount of parenthesizes, only because the opening parenthesis is one symbol to the left, instead of in the middle of the calls...

embedding-shape10• 8 months ago

every declarative language becomes a programming language.

Overly pessimistic, lots of non-programming languages remain non-programming languages. Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down...

The distinction between code, config and data is being erased.

As as lisp programmer, I love it. Get rid of treating things differently, make everything the same and make everything work with everything, code should just be data.

zkmon2• 8 months ago

> Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down.

You need to look at a large terraform project.

bmn__3• 8 months ago

> The distinction between code, config and data is being erased.
As as lisp programmer, I love it.

You make bad engineering decisions because you consider the advantages, but not the disadvantages. <https://news.ycombinator.com/item?id=29231493>

shevy-java5• 8 months ago

Just because one of the most widely used declarative languages start adding conditionals doesn't mean the whole world is turning upside down.

The question still is: why is CSS becoming a programming language? And who decides on this, anyway?

enbugger• 8 months ago

If only Lisp had better presense in modern code editors. Emacs is not enough, especially on Windows where it is super slow. I think this is what actually stops newcomers to start with Lisp and not Python

alwillis4• 8 months ago

A gentle reminder: conditionals aren't new to CSS; @supports and @media are conditionals; so are style queries.

if() just codifies behaviors and hacks [1] developers were already doing.

[1] https://lea.verou.me/blog/2020/10/the-var-space-hack-to-togg...

saghm• 8 months ago

Get rid of treating things differently, make everything the same and make everything work with everything, code should just be data.

"Code should just be data" doesn't imply the converse, though; there's arguably utility in having data that isn't code, even with the premise that code should be data.

drcxd• 8 months ago

Yeah, code is data, data is code. Every Lisp programmer knows that.

marcelr• 8 months ago

can someone interpret this as not a skill issue?

i want better, declarative, interactive, fast UIs

CSS is the best answer we have

IngoBlechschmid• 8 months ago

An interesting example is the Dhall language: https://dhall-lang.org/

It is a configuration language with general programming features, but it is decidedly _not_ Turing complete. It seems to sit at a sweet spot between "just JSON, no programming convenience at all" and "full-blown programming language with nontrivial toolchain".

pragma_x2• 8 months ago

I've been observing this, off and on, for decades now. Is there an actual formal proof or law named after someone at this point?

niutech3• 8 months ago

CSS is already a programming language long before if() function. You can even emulate CPU in it: https://dev.to/janeori/expert-css-the-cpu-hack-4ddj

anon115• 8 months ago

dont be such a doomer

kazinator• 8 months ago

An if conditional doesn't make a programming language. You need recursion to have Turing completeness.

CSS already has all sorts of conditionals that are if() in disguise!

For instance a selector like .foo means "if the class is foo then select this style block'.

CSS is thoroughly condition-driven already.

paulddraper• 8 months ago

Von Neumann devastated

ASalazarMX• 8 months ago

I hope I get to see the next thing after browser applications in my lifetime. I fully understand the advantages, but it has grown so fast and so wild I think it has to eventually fall down by its own weight and complexity despite its immense success.

It's not that the presentation layer need conditionals, it's that the layers under it have grown full of hacks that need more hacks to work around them, because the web was designed to grow documents, not programs.

If the web had been designed for applications in the first place, the presentation layer probably wouldn't need conditionals at all.

EmilStenstrom• 8 months ago

Here is a much better link to how it works: https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/V...

cubefox• 8 months ago

  padding: 1em;
  padding: if(style(--size: "2xl"): 1em; else: 0.25em);

> Note: Remember to include the else condition. In if()-supporting browsers, if no else value were included and --size was not equal to "2xl", the padding would be set to initial.

This is counterintuitive. You would expect the above falls back to "1em" (from "padding: 1em;") when "else" is not specified. Instead, omitting "else" apparently means "else: initial".

kaelwd• 8 months ago

That's the same as regular css variables unfortunately

    padding: 1em;
    padding: var(--padding);

With no fallback value that resolves to padding: unset if the variable is not defined. The only ways I know of to work around this are style queries:

    padding: 1em;
    @container style(--padding) {
      padding: var(--padding);
    }

Or cascade layers:

    @layer base {
      padding: 1em;
    }
    @layer override {
      padding: var(--padding, revert-layer);
    }

nottorp3• 8 months ago

So we were looking in the wrong direction for AGI!

nottorp3• 8 months ago

Replying to myself (hey, I like myself and I'd like to have a conversation with me):

CSS doesn't have it right? Just Chrome.

Considering how all kinds of "experts" have started to make web sites that only work fine in Chrome [1], this is not exactly a useful new feature, more like embrace and extend...

[1] Orange Romania, when will I be able to download my invoices again in Firefox?

jeroenhd• 8 months ago

It's in the draft spec for the CSS Values and Units Module Level 5 (https://drafts.csswg.org/css-values-5/#if-notation)

I don't see Mozilla's or WebKit's positions anywhere, so this is a Chromium-only feature for now.

Incipient• 8 months ago

As long as css remains "so fast it's free" then I'm mostly happy with that - I use css without thinking about optimisations, and I like it like that!

Sesse__4• 8 months ago

You can certainly write slow CSS, and people do :-) JavaScript typically takes up more of the CPU time overall, though.

cryptonym• 8 months ago

It's not free at all. You can profile it with debug tools and find the most expensive selectors to refactor them. You can also write CSS animations that impacts performance/user experience, this can also be profiled.

Sorry but if you use advanced feature and especially on a big DOM, you have to think about optimisations.

mmis10003• 8 months ago

Well, you can actually write slow css if you make real deep nested flex container. And it's not even too rare. You can actually find such example in yhe wild.

The spec of flex layout requires it to layout its child elements several times to compute actual layout. Make it deep and nested without proper constrains will results in n*n*n*n… layout computations and bring down the browser on resize.

cluckindan3• 8 months ago

It’s not even that hard. Use flex for layout and you can instantly see how slow reflow becomes when resizing the window.

jsmailes• 8 months ago

If I'm reading this correctly, Opera added support in an earlier version then took it away again. Any idea why they might have done it? Maybe a browser engine change under the hood?

tanin• 8 months ago

Nice. I've built desktop apps in a few other frameworks e.g. Java Swing, JavaFX, JetBrains Compose, SwiftUI, QT. Nothing is as easy as JS/HTML/CSS. I've realized that the main reason is its robust capabilities e.g rich auto-layouting/positioning capabilities.

Meanwhile in other UI frameworks, you either don't do it or you draw the damn things yourself lol. So, most of the times I'd just not do it.

Adding if is great. It would reduce the need for JS a bit more, which would make the code more maintainable.

Aardwolf4• 8 months ago

Can it already vertically and horizontally center unknown-beforehand-length multi-line text in a single html element, just like non-CSS table cells could already in 1995?

_jzlw2• 8 months ago

align-content: center;

(supported on block elements since sometime last year)

Aardwolf4• 8 months ago

Thanks, seems to work at first sight in combination with text-align for the horizontal alignment!

That means I may finally not need line-height or multi-element tricks for this anymore

Interesting that this is finally there since a year!

I wonder what made them decide to support it finally, since CSS's creation in 1996.

A button never looks professional if the text in it isn't centered, this was a really needed feature and I still can't understand why it took that long

Edit: it does seem worrying that for me this property vertically centers but not horizontally while the description of it doesn't say vertical but is: "The items are packed flush to each other in the center of the alignment container along the cross axis."

JimDabell2• 8 months ago

Can it already vertically and horizontally center unknown-beforehand-length multi-line text in a single html element, just like non-CSS table cells could already in 1995?

Non-CSS table cells have never been able to do that – you need a wrapping <table> at minimum for browsers to render it how you want, a <tr> for it to be valid HTML, and <tbody> comes along for the ride as well as an implied element. So that’s four elements if you want to centre vertically with <td> or <th>. If you wait until the year 2000, then you can get that down to three elements by switching from HTML to XHTML because <tbody> is no longer implied in XHTML.

CSS, on the other hand, has been able to do what you want since 1998 (CSS 2) with only two elements:

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
    <title>.</title>
    <style type="text/css">

        html,
        body {
            height: 100%;
        }

        .outer {
            display: table;
            width: 100%;
            height: 100%;
        }

        .inner {
            display: table-cell;
            vertical-align: middle;
            text-align: center;
        }

    </style>
    <div class="outer">
        <div class="inner">
            Test<br>
            Test<br>
            Test<br>
            Test<br>
            Test<br>
            Test
        </div>
    </div>

(I’m using a <style> element here for clarity, but you can do the same thing with style attributes.)

https://www.w3.org/TR/1998/REC-CSS2-19980512/

17186274403• 8 months ago

width: fit-content; margin: auto;

Aardwolf4• 8 months ago

That changes the width, I guess I should have specified fixed width

chipx86• 8 months ago

I'm pretty happy to see this, as conditionals can really help keep code manageable when trying to define CSS variables or other properties based on combinations of light mode, dark mode, high-contrast, contextual state in a document or component, etc.

if() isn't the only way to do this, though. We've been using a technique in Review Board that's roughly equivalent to if(), but compatible with any browser supporting CSS variables. It involves:

1. Defining your conditions based on selectors/media queries (say, a dark mode media selector, light mode, some data attribute on a component, etc.).

2. Defining a set of related CSS variables within those to mark which are TRUE (using an empty value) and which are FALSE (`initial`).

3. Using those CSS variables with fallback syntax to choose a value based on which is TRUE (using `var(--my-state, fallback)` syntax).

I wrote about it all here, with a handful of working examples: https://chipx86.blog/2025/08/08/what-if-using-conditional-cs...

Also includes a comparison between if() and this approach, so you can more easily get a sense of how they both work.

bradly2• 8 months ago

I recently implemented dark/light mode for the first time and was really surprised to find that in order to add a toggle I had to duplicate a both of vars/styles and use JavaScript. I'm looking forward to not having to deal with that cruft in the future.

hebelehubele2• 8 months ago

You can do without javascript. Checkbox `:checked` + `label` trick for toggling states still works.

See: https://codepen.io/abdus/pen/bNpQqXv

manucardoen• 8 months ago

Somewhere, someone has just started porting Doom to CSS.

layer8• 8 months ago

I guess we can now write Excel in CSS.

fuzzfactor2• 8 months ago

Interesting, a few organizations can (very) carefully craft their own LOB software over the number of years it can take to fully free themselves from Excel. And then realize the intended advantage for years to come.

At the same time over a period of years the web approach is to make the whole thing more like a bunch of interlocked Excels, more so than it already was before.

Does that mean any resulting disadvantage during following years is intentional? Any more than huge orgs grew to depend on Excel, one physical desktop at a time since that was the only thing in common among all those diverse desk owners that would do the job, plus it was the first thing to come along to fill that niche.

marcinignac• 8 months ago

Proposed title change "Chrome now has an if() conditional function in CSS"

phplovesong• 8 months ago

Now we just need a while loop to make it turing complete.

nake89• 8 months ago

Loops would be nice. To make cool fireworks animations with CSS, you basically need to use SCSS to CSS compiler: https://codepen.io/hmaw/pen/qBEMLxV

qwertytyyuu• 8 months ago

oh no, this is going to cause abomninations,

neuralkoi• 8 months ago

Quick, someone get DOOM running on CSS!

James_K• 8 months ago

How about giving me the option to use variables in media queries?

sethops1• 8 months ago

Yeah this one seems like such low hanging fruit and would be a great convenience.

dsnr• 8 months ago

Next I want to run WASM inside CSS. W3C, please don’t disappoint.

markaroo• 8 months ago

if (it's fast) { i'm excited }

rcarmo2• 8 months ago

Is it Turing-complete yet? Seems close, but I've lost track.

bmn__3• 8 months ago

https://gwern.net/turing-complete#:~:text=CSS

hasbot• 8 months ago

Huh. 35 year ago I was the sole maintainer of an in-house SQL-like database query language. The application was transforming relational data into a more concise and efficient format for use in an embedded application (AT&T 5ESS digital switch). All the mapping was done in this SQL-like language. One of my power users mentioned the difficulty they had in actually changing logic based on the values in the database. For example, to perform different logic based on whether a column was a 1 or a 2, they'd have to write two querys: one for 1 and another for 2. Possible, sure, but not very clean or efficient. To address this, I implemented an if() function.

shevy-java5• 8 months ago

They want to turn it into a programming language ... :/

zombot• 8 months ago

How long before CSS can run Doom?

anthk3• 8 months ago

Nice, does it make turing complete? If so, another crap to block under Dillo.

That's what happens when you design a language by comitee (C++, JS) and try to do stuff in the web for a platform made to share static documents.

Just look at what kind of disasters the users faced with Office macros.

trollbridge• 8 months ago

One of the nice things working in vite is realising, “hey, this config file is just {Java,Type}Script”.

vaylian• 8 months ago

Not supported in Firefox

Pwntastic2• 8 months ago

just a meta note that the submitter, aanthonymax, likely only posted this to launder karma to avoid being shadowed for spamming their github project. a quick look at their post history shows that they only post links to their github project and then occasionally extremely low effort random mdn or other useless links to try to balance our their account. their previous account was shadowed for basically the same thing

matheusmoreira• 8 months ago

This stuff makes me paranoid about posting my projects here and everywhere. Don't want to be seen as advertising my code...

Pwntastic2• 8 months ago

it's one thing to openly self-promote your project, and another thing to have created multiple accounts that spam links to your project on a weekly basis

moritzwarhier• 8 months ago

I'm kind of thankful not having to work with people trying to be clever in CSS anymore (especially "clever" backend developers).

And I used to defend and evangelize taking HTML&CSS seriously in my previous roles, which I'd still do!

But as much as I have longed for features like these in the past (also: :has(), container queries, custom properties...), I dislike this.

I found CSS grid disappointing for most use cases.

I think :has() is a terrible idea, except for quick hacks.

I still think container queries and custom properties are good.

But, oh well, old man yelling at cloud.

mxey• 8 months ago

Haven’t seen this mentioned yet, but this means you can do media queries in inline styles, right?

CSS now has an if() conditional function

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