The Two Great Things About Validation

Post from January 30, 2009 (↻ June 1, 2020), filed under  (feed).

This and many other posts are also available as a pretty, well-behaved ebook: On Web Development.

There are two great things about validation: Validating helps technical understanding as it contributes to awareness of the underlying specifications, and writing valid code is a sign of professionalism.

Put another way, developers who don’t validate miss important opportunities to learn, and invalid code can in most cases be considered unprofessional.

However, invalid code doesn’t necessarily mean inaccessible or unmaintainable code. That’s a myth. You can invert that statement, too, though: Valid code doesn’t mean accessible or maintainable code, nor efficient or fast code.

From my comment on Valid sites work better (?). Revised.

Toot or tweet about this?

About Me

Jens Oliver Meiert, on September 30, 2021.

I’m Jens, and I’m an engineering lead and author. I’ve worked as a technical lead for Google, I’m close to W3C and WHATWG, and I write and review books for O’Reilly. I love trying things, sometimes including philosophy, art, and adventure. Here on I share some of my views and experiences.

If you have a question or suggestion about what I write, please leave a comment (if available) or a message. Thank you!

Comments (Closed)

  1. On January 30, 2009, 14:44 CET, olivier said:

    Hi Jens,

    it looks like our CMS ate your comment or something to that effect, I can’t see your comment in the (empty) pending queue. Can you resend?

  2. On January 30, 2009, 14:54 CET, Jens Oliver Meiert said:

    Olivier, sure, I just submitted the comment again (twice, actually, the latter fixing a broken link).

  3. On January 30, 2009, 17:34 CET, olivier said:

    Published! Thanks Jens for your patience.

    I find it a bit scary that comments migh be lost like that, though…

  4. On January 31, 2009, 6:24 CET, Jared Smith said:

    Excellent post - and right to the point.

    Replace “validation” with “alt text in HTML 5″ and you pretty much sum up my thoughts on that point also. Alt doesn’t make it accessible and missing alt doesn’t make it inaccessible, but having a guideline for implementing it educates, supports accessibility, and is professional.

  5. On February 2, 2009, 19:53 CET, Jens Oliver Meiert said:

    Thanks, Olivier, Jared!

    Regarding @alt, Jared, yes, that debate may be philosophical đŸ˜‰

  6. On February 10, 2009, 12:43 CET, Richard Morton said:

    Although I would agree that invalid code doesn’t have to mean inaccessible or unmaintainable code, I would say that valid code is definitely easier to maintain.
    The big link between accessibility and validation is that valid code should behave more predictably across different browsers than invalid code. Of course that is a utopian view as browsers don’t just treat invalid code differently.

  7. On July 7, 2013, 2:18 CEST, Alistair Lattimore said:

    I agree valid code is a sign of professionalism but it can’t be a black and white scenario, as a lot of publishing platforms still get in the road of idealistic outcomes like W3C validation.

    I say idealistic because browsers are largely indifferent to valid HTML versus invalid HTML, rightly or wrongly - that is just how things are.

    Given that browsers are so tolerant of valid or invalid HTML/CSS, what would you prefer in general:

    1) lean but invalid HTML/CSS or;
    2) bloated but valid HTML/CSS