Comment by jraph
15 days ago
In the linked article:
> you should master the HTML programming¹ language
The footnote reads:
> 1. This is a common debate - but for simplicity sake I'm just calling it this.
It's not really a debate, HTML is a markup language [1], not a programming language: you annotate a document with its structure and its formatting. You are not really programming when you write HTML (the markup is not procedural) (and this is not gatekeeping, there's nothing wrong about this and doesn't make HTML a lesser language).
To avoid the issue completely, you can phrase this as: "you should master HTML" and remove the footnote. Simple, clean, concise, clear. By the way, ML already means "Markup Language", so any "HTML .* language" phrasing can feel a bit off.
Of course HTML is a programming language. It's one of the languages I use every day to program with. I'm not sure what the definition of a programming language would be beyond that.
Do you mean "Turing-complete" language? Or maybe "procedural programming language"? I agree HTML isn't either of those, but those aren't the be-all and end-all of programming now, are they?
I, and most of us, mean a language in which one can express a computer program, which is a set of instructions for a computer to execute. You don't execute an HTML file, you display it, render it. You can't implement fizz buzz in HTML. At best, you mark up its output. With HTML, you don't instruct, you describe. You instruct what to do with JavaScript, or Python, or whatever programming languages you use client or server side.
A programming language doesn't need to be procedural, it can be functional, or use another computationally equivalent paradigm. I'm not quite sure it needs to be Turing complete, but possibly.
A programming language lets you express to some processor that provides a set of computation primitives what to do with the memory cells you have at your disposal, and in general it lets you deal with input and output.
If you consider any language you program with to be a programming language, then CSS, JSON, YAML, XML, markdown (that's what your readme is likely written in) and even English (that's what you use to express the specs, the bugs, maybe your notes / drafts, the comments, possibly the language the singer of the songs you're listening to while programming use) or UML need to be programming languages too. That's not quite useful. "Program with" is too large and would make the "programming" qualifier largely useless.
https://en.wikipedia.org/wiki/Programming_language
https://en.wikipedia.org/wiki/Computer_program
https://en.wikipedia.org/wiki/List_of_programming_languages
https://stackoverflow.com/questions/14512218/is-html5-a-prog...
An HTML file is a set of instructions to execute. They're very high-level, declarative instructions for describing a UI, similar to how SQL is high-level declarative instructions for describing a set of data to be loaded, or how Prolog is a high-level declarative set of instructions for describing a set of logical axioms, but they're still instructions. You pass them to an execution engine, and on the basis of the instructions you've written, the engine does something. (See e.g. the section on fourth generation PLs in the second link you gave.)
More broadly, I think this discussion is a stupid one. There is no formal, mathematically precise definition of a programming language. There are formal definitions of lots of PL-related things, and for what a language is in general (a combination of syntax and semantics), but there's no formal definition of the term "programming language" that's useful here.
So if we're not arguing about a formal definition, then we're arguing about essentially our favourite dictionaries, and how we personally interpret our favourite dictionaries. And that's just not a useful argument at all, it's not even how dictionaries are meant to work! And yet whenever someone dares to write "HTML programming language" or something similar, there is always a comment from someone demanding that the author use their personal dictionary, and correct their changes. And it is deeply grating, because whenever I see this happen:
* The original statement is never ambiguous. I have never seen a situation where referring to HTML as a programming language has ever caused some sort of confusion.
* The discussion about whether HTML is a programming language is almost always completely irrelevant to the topic at hand, and bringing it up adds no value to the discussion.
* The author's definition is usually inconsistent anyway. Which isn't a problem — I don't imagine my mental definition of a programming language is entirely consistent either — but it's dumb watching someone try and correct other people without understanding their own definition enough to be able to respond to clarifying questions.
In your original comment, you said "it's not really a debate", and that's completely correct. It's not a debate because there's no right answer. There's not even any value to a right answer. The matter is entirely a question of terminology. And if different choices of terminology make things unclear, then it might be worth clarifying that terminology, but here I don't think the author could have been any clearer at all about what they were trying to communicate.
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What happens if I simply add an iterator mechanism to HTML (well, I guess we need variables too)? Is it no longer a markup language here (I won't add anything else):
<for i=0; i<1; i++> <html> </html> </for>
Better question, why don't we upgrade XML to do that?
That's not technically HTML anymore.
But if you disagree with this, or somehow work around this statement by replacing your for element with some "for-loop" custom element (it is valid HTML to add custom tags with dashes in their names), my stronger argument is at https://news.ycombinator.com/item?id=46743219#46743554
> Better question, why don't we upgrade XML to do that?
XSLT which is an application of XML allows you to do a for-each: https://developer.mozilla.org/en-US/docs/Web/XML/XSLT/Refere...
That's basically the design of PHP with different syntax. <?for($i=0;$i<1;$i++){?> <html></html> <?}?>
Nobody uses PHP this way any more though — people treat it like Python or Node and write the entire codebase inside a big <? block
JSP is similar with different syntax again — nobody uses JSP either
I think ASP too but I never used that
You could have some client side JavaScript handle your for nodes as well. That's how I imagined what OP described actually.
> Nobody uses PHP this way any more though
Well… I have bad news.
I do, for one :-)
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If HTML was never able to be the full solution, then I guess if I had to expand on where I'm going, then what the heck are we even doing with this html thing? Either MAKE IT like PHP, ditch it, or do something, anything.
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I dunno, you're being pedantic :) Yes yes, the name clearly ends up "Markup Language" so yeah, with a very strict definition of programming languages, HTML is not one of them.
But if we use a broader definition, basically "a formal language that specifies behavior a machine must execute", then HTML is indeed a programming language.
HTML is not only about annotating documents or formatting, it can do things you expect from a "normal" programming language too, for example, you can do constraints validation:
That's neither annotating, just a "document" or just formatting. Another example is using <details> + <summary> and you have users mutating state that reveals different branches in the page, all just using HTML and nothing else.
In the end, I agree with you, HTML ultimately is a markup language, but it's deceiving, because it does more than just markup.
> I dunno, you're being pedantic :)
It might be, I'm usually not, but this is all xhtml.club and this footnote are about, might as well be correct :-)
Constraint validation is still descriptive (what is allowed)
All details and summary are doing is conveying information on what's a summary and what's the complete story, and it has this hidden / shown behavior.
In any case, you will probably find something procedural / programming like in HTML, but it's not the core idea of the language, and if you are explaining what HTML is to a newbie, I feel like you should focus to the essential. Then we can discuss the corners between more experienced people.
In the end, all I'm saying is: you can just avoid issues and just say "HTML" without further qualifying it.
> behavior a machine must execute
This is not what HTML does. Tags are not instructions, they delimit the start and end of elements. They describe content, they do not specify behaviour.
In your pattern example, that is still just a description of what is acceptable input. It doesn’t execute anything. A paper form might specify the format DD / MM / YYYY but that doesn‘t mean the form is executing a program in your brain when you fill it out.
I'm not sure we can call your parent comment pedantic. They're just being correct. Is it pedantic to say that fish is not a fruit? It's just correct to do so.
If anything, it is the act of stretching the definition of "programming language" so much that it includes HTML as a programming language that we should call pedantic.
One threshold is "can you write a program that might not complete?" You can't in SQL, which makes it less of a programming language than, say, FORTRAN.
If you look at the HTML 5 spec it is clear that it's intended to be a substrate for applications. The HTML 5 spec could be factored into a specification of the DOM, specification of an x-language API for the DOM and a specification for a serialization format as well as bindings of that x-language API to specific languages like Javascript.
> If you look at the HTML 5 spec it is clear that it's intended to be a substrate for applications
That's the saddest thing I've read today.
(arguably not a terribly sad day)
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consider the following:
https://html-lang.org/
Oh yes, this is "HTML, the programming language", not HTML (also called "HTML, the markup language" in that page).
And it's brilliant :-)
I think that it is a debate, and it depends on the role of HTML in your system.
If all you're doing is using HTML to "annotate a document with its structure and its formatting", then yes, I'll accept that it's not quite programming, but I've not seen this approach of starting with a plain non-html document and marking it up by hand done in probably over two decades. I do still occasionally see it done for marking up blog posts or documentation into markdown and then generating html from it, but even that's a minuscule part of what HTML is used for these days.
Your mileage my vary, but what I and people around me typically do is work on hundreds/thousands of loosely coupled small snippets of HTML used within e.g. React JSX, or Django/Jinja templates or htmx endpoints, in order to dynamically control data and state in a large program. In this sense, while the html itself doesn't have control flow, it is an integral part of control flow in the larger system, and it's extremely likely that I'll break something in the functionality if I carelessly change an element's type or attribute value. In this sense, I'm not putting on a different hat when I'm working on the html, but just working on a different part of the program.
> React JSX, or Django/Jinja templates
Those are not HTML. PHP neither, even when used as a templating language for HTML.
> htmx endpoints
Not really familiar with htmx, but I would say this is HTML augmented with some additional mechanisms. I don't know how I would describe this augmented HTML, but I'm not applying my "not programming" statement to htmx (I probably could, but I haven't given enough thoughts to do it).
> In this sense, I'm not putting on a different hat when I'm working on the html, but just working on a different part of the program.
I agree with this actually. I wouldn't consider that writing HTML (or CSS) is really a separate activity when I'm building some web app.
> In this sense, while the html itself doesn't have control flow, it is an integral part of control flow in the larger system
That's correct but I don't see what it has got to do with the question of whether HTML is a programming language or not.
Strings do not have control flow but strings are integral part of larger programs that have control flow. So what? That doesn't make strings any closer to being programming languages.
It's a question of semantics. What I'm saying is that the way many of us use html in practice in 2026 is less like arbitrary strings and more like db connection strings, where most of our focus is not on whether a bit of text is an article or an aside, but about how it participates in the control flow across different components in our architecture.
From another perspective, I'm not familiar with any present day company, where the html they use in their source code is sufficiently simple and distinct from the rest of the program to be managed by non-programmers. The only html that is just used as strings is that used for individual posts in a crm or marketing tool's cms, typically stored in a database rather than the source code repository.