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* { box-sizing: border-box } FTW (paulirish.com)
348 points by tambourine_man 1834 days ago | hide | past | web | 85 comments | favorite

As it's been said in the comments, it's amazing that after years of lobbying IE to change its box model to match W3C, we realize that maybe IE's model made more sense after all.

> it's amazing that after years of lobbying IE to change its box model to match W3C, we realize that maybe IE's model made more sense after all.

Not really. Everybody I've known (in about a decade) has felt the IE box model made more sense.

But here's the thing: it wasn't the standard, the standard was not going to change its default box model, and dealing with a single slightly worse box model would always be better than dealing with two completely different box models.

box-sizing is the alternative, and a pretty good one. But I don't think anyone ever read about the differences between the W3C box model and the MSIE box model and thought "wow, the W3C box model makes so much more sense".

I've felt for years that the "broken" IE model made more sense. Your element has a height and width, padding pushes inward against interior content and margin pushes outward against exterior content.

Glad to see others think this too, I always thought it was just me.

>padding pushes inward against interior content and margin pushes outward against exterior content.

That actually seems the wrong way round to me. If you think about a document, the margin is what separates text from the edge of the page (or interior padding, if you will). Padding, to me, implies an area around an element that other elements can't touch.

No, you're looking at it the wrong way. What you call the paper's margin is actually the paper's padding. Or better yet, when you are setting the margin of a document you are actually setting the margin of all the text on the document to the defined width.

Yes, you're right, that makes more sense. Now let's never bring this up ever again for fear of confusing people some more.

People were lobbying for IE to change in order to make it consistent with the rest of the browsers, not necessarily because it was worse.

Yeah, but why not lobby W3C to change their box model to a saner one?

That's what `box-sizing: border-box` is! You can't just change the default because that would break existing websites and the W3C's box model was adopted by every other browser.

Sure you can change the existing default, that's what people wanted IE to do.

If individual vendors mess up when implementing the spec from the standards body (which they are a member of) then they should have to clean up their own mess. IE did eventually change the default in IE6 and added quirks mode for compatibility with websites designed for <IE6.

Even if the majority of people preferred the IE5.5 box model, it didn't follow the spec and it is therefore wrong. We have standards specifications on the web to maintain cross-browser compatibility; if browser vendors don't follow them then whats the point?

Even if the majority of people preferred the IE5.5 box model, it didn't follow the spec and it is therefore wrong

Specs should standardize what's generally considered a good idea. They are not written in stone and have no value in and on itself. If IE's old model was consensually better (and I'm not sure it was), the spec should have changed, not the other way around.

After all these years writing CSS, I'm very biased and it's hard to evaluate which is better. I was aware of border-box, but I thought it was Webkit only. Though I probably won't make the switch altogether, I'm glad to know we have a choice.

Points to TFA

I think IE worked this way only if there was no DOCTYPE. Or am I mistaking this with some other IE "bug"?

Prior to IE6 it worked this way all the time. That's why quirks mode was there in later versions.

Yeah, it was quirks mode.

This article was an eye-opener - I write CSS all the damn time and hadn't even clocked box-sizing yet.

I don't wanna know how many hours I've spent calculating widths-after-padding(-but-wait-it's-different-on-both-sides) and commenting the CSS so other developers know why this element is width: 169px even though the container is 200px...

Not to mention:

    textarea { width:100%; padding:20px; oh shit. }

Wow, yeah. For years I've been using the container-div idiom, where the outer one sets the width, and the inner one imposes border and padding against a width: auto.

This may take some getting used to.

I can't tell you how much I enjoyed doodling in the margins while I read that article.

What article?


I don't know what I did, but after I doodled a bit and scrolled the page around using the middle mouse button, this youtube video popped up over the page: http://www.youtube.com/watch?v=E6x_-xKl-Fg

Also the konami code makes the same sort of unicorns appear that were on the video.

Drawing a star causes the video to appear.

I tried drawing every kind of star I know but couldn't get any video to show.

You have to draw the (5 pointed) star from the bottom left - like this : http://depts.washington.edu/aimgroup/proj/dollar/

Because I know we all wanted it.

http://jsfiddle.net/gSD94/2/ http://jsfiddle.net/gSD94/2/embedded/result/

(great article too!)

edit: better link (fullscreen!)

Nice work. I talked about the effect back at http://paulirish.com/2010/my-harmonious-background-canvas/

And the equivalent code is available on Github: https://github.com/paulirish/harmony

Thanks for the code, it's awesome fun to play with. :)

To those wondering:

Harmony procedural drawing tool, by mrdoob: http://mrdoob.com/projects/harmony/

dollar recognizer project (draw a star on paul's background!): http://depts.washington.edu/aimgroup/proj/dollar/

inspired by paul's site's implementation, about a year ago, i made a proof of concept captcha thing ("motioncaptcha"): http://www.josscrowcroft.com/demos/motioncaptcha/

As I pointed out on twitter http://twitter.com/#!/jhummel/status/169561232045649921 it seems that the * selector doesn't apply to pseudo elements. If you're going to take this route it might be a good idea to include *, ::after, ::before { box-sizing: border-box } to make sure everything is being sized the same.

Where the traditional box model starts to make sense is with fixed-size elements, such as images. Adding padding to an element shouldn't alter the dimensions of the contents within the element.

Yes it should. If you don't want that space to be from within the element, then you should be setting a margin, not a padding.

Box analogy: when you add foam padding to a box to protect its content, are you effectively widening the box or reducing the volume it can fit?

Using your analogy, if I have to transport an item, and I want to pad it sufficiently, I should be looking for a bigger box. Not trying to shrink the item.

Good point. Maybe the best thing then is to add a rule for "img" or maybe ".fixed-size" with "box-sizing: content-box" right after after the "*" rule.

I didn't read the article, but love the mouse effects outside of the content area :D

The Firefox on my work desktop (7, Linux) slows to a crawl on that site, I suspect it's because of the doodle effect. Annoying gimmick, sorry.

Firefox canvas performance is a joke. You should upgrade to Chrome.

Firefox (10, linux) performance is fine for me; it may be his browser version or something else.

Works fine on my own machine (13, Linux). But that doesn't help people who are stuck on machines where it doesn't. I suppose the code could detect low frame rates and reduce quality or shut down?

I read the article, then proceeded to waste another 20 mins of my works time drawing phallic images in the sidebars.

Still, very cool trick, and the drawing is incredibly smooth.

Harmony.js: There you go > http://mrdoob.com/projects/harmony/

Although, I don't find harmony.js a very nice way sorts.

I love you Paul Irish. I was just complaining about this exact same issue about 3 days ago and when I found this article I was like YES HE AGREES WITH ME!

Especially when dealing with fluid layouts, this guy is a lifesaver

Yes, trying to do fluid layouts with percents and borders is a huge pain without this. Too bad it doesn't work with IE7 as I'm still seeing about 5% market share from there. But at least it's declining fast.

Weird timing - after years of coding I literally found this box-sizing solution today on SO just a couple hours before seeing it here on HN.

Yeah same, found it like 3 days ago and was like thank god. I'm going to create a fix for IE7, whether it's a polyfill or sass wizardry, and I'll make a post about it when I do. Easy fluid responsive layouts for all!

Good god, it's about time this hits the mainstream dev community.

The W3C box model is IMO one of the worst design flaws in front-end dev. It's a model that doesn't follow that of a real box! When you have padding (stuffed newspaper, peanuts, etc) in a packing box, the actual width and height of the box doesn't change! Border-width(or the thickness of the cardboard) is also included in the box dimensions.

I've only heard very weak reasons in the past for the W3C version and I'm surprised we haven't gotten past it. I think border-box will become more important as we head towards cross-platform responsively designed apps and sites with tons of layout decisions to consider. With simple sites up until now, you could afford the loss of control or the cognitive overhead to figure out workarounds. But now, I don't want to think the unintuitive way every time I'm making a layout decision for different screens.

I've found border-box to be especially helpful with mobile layouts. I can set the width of my text inputs to 100% and not worry about weird side-scrolling breakage. And of course save time by not having to specify widths for the inputs. or max-widths or whatever.

I wrote about the same CSS with a small plea that CSS 3 be ratified and implemented across all browsers as quickly as possible:


I was working on my portfolio site (link in my profile) and was frustrated with the CSS layout rules. It makes a lot more sense (at least to me) for the way it works with box-sizing: border-box than what it was previously.

If I were not afraid of having my portfolio site also easily accessible by HR in various different companies (many still with IE 6) I'd have used the experimental tags. Instead I used a work-around.

Somewhat related is the ability to do calculations in CSS3, allowing you, for example, to subtract pixels from percentages.


Incredible. I wish someone had told me this a few years ago, would have saved me a ton of grief. Jeremy Keith said it best in the comments: "box-sizing: border-box is the bee's knees."

The way I have been getting around this until the last year or so was just double wrapping divs. Setting a wrapper to have the width you want with 0 margin and padding, and then assigning the padding and margin you want to the inner div does essentially the same thing

Right, exactly, and in a complex layout that adds a significant amount of extra markup. Not to mention trying to find which of the 4 or 5 columns is the one that's breaking the width of their container and causing the last column to break below the rest. It works, and has worked for me for a long time, but it's a hack.

oh, without a doubt. I kissed the earth when I found that IE 8 supported border-box, my point was just that there were hacks around the issue before now.

I also had to do that sometimes... but it make your code a lot more complex if you use it a lot.

Well, if you'd found out about it a few years ago you'd plausibly still have felt an obligation to support IE7, and thus been unable to use it.

Just wait until you discover Flexbox!

And all those years I was wondering if I was stupid to think that.

I'm eager to use it, but as I use Bootstrap I imagine it breaks it ?

Not as badly as you might think! Playing around with the new box model on a test site and on the bootstrap site (via firebug), I only found four noticeable changes in appearance:

- The search form was noticeably shorter and more cramped. I fixed this by adding height: 100% to the interior text input element

- Text inputs are less wide than they should be when you use bootstrap's span classes

- The navbar's vertical and horizontal dividers disappeared. I fixed this by adding 1px of padding to either the side or bottom of the divider, as the case required.

- Side tabs are a less wide than they should be

Was I the only one that for some reason got a Youtube-video that all of a sudden popped up and started playing a short video about ESPN being hacked or something?

Might have been a glitch of some sort, but I'd suggest OP should check his source code to see if he hasn't been compromised of some sort.

omg hacked! Nah it's cool. I wired that up. The unicorns konami trigger that was featured in the video was introduced by my blog so it's a bit of an homage or something. Thxthx.

Hey for some reason I can't add your Google Reader Frontend feed collections to my subscriptions. Clicking on the "Subscribe" buttons doesn't produce any result. Win XP and Chrome here.

Not having IE7 support is a pretty nasty limitation though, if you're developing a commercial web site.

I wonder if anyone wrote an IE .htc script to ix this dynamically.

Maybe forcing the browser into quirks mode would do the trick?

I worked on a project recently where the previous designer did this and it was absolutely maddening. Switching the box model can be useful sometimes, but it makes no sense to me why you would do this globally.

My initial thought is that it only makes sense to do it globally. Two different box models in the same page - now that would be maddening.

I wonder how well this works with Bootstrap?

TIL about calc()


Paul is there an answer to this: http://stackoverflow.com/questions/8421533/how-to-obtain-ctr...

You'll know, so I am asking it here. Or is it even a right question in the first place?

Answered you on SO. :)

Thanks a lot Paul.

I have learned a lot from your work on Boiler Plate, HTML5 and Modernizr. Let me dig deep into zooming and come up with its results.

Your background is just awesome! :D

Will this work with older browsers? Where can I expect support for this?

The article explains that in full

(everying apart from <=ie7)

Could you not just trigger quirks mode in IE6 and IE7 to get the old box model, or is border-box different to the old microsoft box model?

The old microsoft box model was basically this one, but the implementation was so full of bugs that it ended up being "test and change until it shows the way you want".

There are even lists compiling those bugs, such as http://www.positioniseverything.net/explorer.html

The W3C box model spec forms a set of consistent rules that make sense. It's not the spec that's wrong. Just because it doesn't fit with your original intuition doesn't make it wrong.

It's not just an issue with intuition it simply makes it far harder to do many types of layout.

One of the biggest failings of the W3C model was that you could not combine a percentage width with fixed margin. If you wanted a fluid layout but which still incorporated consistent margins it was impossible to achieve without an entirely unnecessary nesting of divs.

Border-box completely eliminated this and poor old Microsoft (in this one instance) were forced to fall in with the less helpful "standard".

Content-box eliminated this?

A spec that doesn't work the way most people think about the problem and that makes it harder to do what you want in a page layout is wrong more or less by default.

The W3C box model would only be useful if the W3C also provided a way to specify a width as "percentage of parent box width minus a fixed number of units" to compensate for the padding adding to the total width.

However, they did not, which means that in order to make a decent flowing layout, you have to change your document markup to insert artificial and otherwise unnecessary elements (DIV tags usually).

Thus the original model was flawed, did not make sense, and ultimately was not consistent with their own stated goals (separation of content and style).

[edit: FWIW petenixey said essentially the same thing, and what's really clever is that he said it first.]

At this point the W3C is in fact working on providing such a thing. "width: calc(50% - 20px)".

Works in Firefox and IE. At some point WebKit will catch up, I assume.

I'm glad to hear that, but it's long overdue and the border-box model already solves the same problem with less markup (and most importantly, without creating an implicit dependency between the padding and width styles).

Well, in all fairness calc() lets you solve a bunch of problems that border-box can't solve.

Not wrong in that it is broken in some way, but it is possible for people to look at it and decide it was the wrong decision to make.

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