Search code examples
cssnaming-conventions

CSS class naming convention

On a web page, there are two blocks of controls (primary and secondary), what class names would most people use?

Choice 1:

<div class="primary controls">
 <button type="button">Create</button>
</div>

<div class="secondary controls">
 <button type="button">Edit</button>
 <button type="button">Remove</button>
</div>

Choice 2:

<div class="primary-controls controls">
 <button type="button">Create</button>
</div>

<div class="secondary-controls controls">
 <button type="button">Edit</button>
 <button type="button">Remove</button>
</div>
Solution

  • The direct answer to the question is right below this one, by Curt.

    If you're interested in CSS class naming conventions I suggest to consider one very useful convention named BEM (Block, Element, Modifier).

    UPDATE

    Please read more about it here - http://getbem.com/naming/ - that's a newer version that renders the following answer obsolete.

    Main principles:

    • A page is constructed from independent Blocks. Block is an HTML element which class name has a "b-" prefix, such as "b-page" or "b-login-block" or "b-controls".

    • All CSS selectors are based on blocks. There shouldn't be any selectors that aren't started with "b-".

    Good:

    .b-controls .super-control { ... }

    Bad:

    .super-control { ... }
    • If you need another block (on the another page maybe) that is similar to block you already have, you should add a modifier to your block instead of creating a new one.


    Example:

    <div class="b-controls">
    <div class="super-control"></div>
    <div class="really-awesome-control"></div>
</div>

    With modifier:

    <div class="b-controls mega"> <!-- this is the modifier -->
    <div class="super-control"></div>
    <div class="really-awesome-control"></div>
</div>

    Then you can specify any modifications in CSS:

    .b-controls { font: 14px Tahoma; }
.b-controls .super-control { width: 100px; }

/* Modified block */
.b-controls.mega { font: 20px Supermegafont; }
.b-controls.mega .super-control { width: 300px; }

    If you have any questions I'd be pleased to discuss it with you. I've been using BEM for two years and I claim that this is the best convention I've ever met.