Object oriented CSS

I watched this presentation about object oriented css, but I think I either don't understand it correctly or don't understand the benefits of using OO CSS:

Example HTML:

<div class="border-1 bg-2 color-1 font-1开发者_JAVA百科">
</div>

Example CSS:

/* borders */
.border-1 { border: 1px solid red; }

/* backgrounds: */
.bg-2 { background: yellow; }

/* other sections */

I see an advantage in being able to change styles for multiple elements quickly, for instance, being able to switch the color scheme would be very useful.

But actually, you're defining the style/look inside the HTML, or at least a part of it. Of course, it's better than using the style attribute, because you still are able to exchange the styles for a set of groups.

The point is, you are defining the style-groups inside the HTML, but I learned that you should create "logical" groups inside the HTML (e.g. class="nav-item" / class="btn submit-btn") and the CSS completely applies the style and defines which elements belong together from the "stylistic" point of view (e.g. .nav-item, .submit-btn { background: red; }).

Maybe I totally misunderstood the concept. However, I still don't know a good way of constructing my CSS.

CSS isn't object oriented. My suggestion is to forget what you've read about "object oriented CSS" and instead focus on the problems with CSS you're trying to solve. If they are to make CSS easier to write, read and maintain, or to get more features (like CSS variables) I think Less or Sass will suit your need much better.

Using CSS like what's suggested with "object oriented CSS" just leads to terrible, non-semantic and meaningless CSS that in the long run isn't any easier to maintain than "ordinary" CSS. Both id and class should have semantic and meaningful names, so using a framework that allows you to write semantic CSS (that describes intent instead of presentation) is in my humble opinion much better.

This is more of a "name dropping", that an actual method. The code that you have shown is often derogatory called "enterprise css", there is no excuse for it.

More over, having multiple classes on elements actually hurts performance.

I advice you to adhere to Mozilla's guidelines when making your CSS, which works same for other browsers, too. And make dedicated .css file with hacks for IE6, 7 and 8.

The idea is that you reuse the same css classes on many elements. This both saves on writing css and on maintaining css. so instead of defining .create-button .cancel-button .create-and-new button you would just have a .button that defines padding, size, background, color, line-height, font-size, font-family and font-weight. And some really small classes for the different button styles like to change the color or font-size

a proper oocss project I often still use can be found here: https://github.com/stubbornella/oocss/wiki

but yes you should have a look at less, it combines the easy of reusing the same css properties on multiple elements with proper class names.

"Object-oriented CSS" is really just a design pattern for how to get most out of your CSS and is basicly the same approach Jonathan Snooks calls SMACSS.

Whether you call it OOCSS or SMACSS, the key to the approach is that you create generic UI elements like the nav abstraction. These UI elements can then be enhanced with more specific features by adding extra classes to the element and/or a container element. Or, as an alternative, you can add your own custom CSS rules using the element's ID or semantic classes.

Further reading :

• An Introduction To Object Oriented CSS (OOCSS)
• OOCSS + Sass = The best way to CSS