HTML style guide

See also our accessibility best practices.

Semantic elements

Semantic elements are HTML tags that give semantic (rather than presentational) meaning to the data they contain. For example:

Prefer using semantic tags, but only if the intention is truly accurate with the semantic meaning of the tag itself. View the MDN documentation for a description on what each tag semantically means. 

<!-- bad - could use semantic tags instead of div's. -->
<div class="...">
  <p>
    <!-- bad - this isn't what "strong" is meant for. -->
    Simply visit your <strong>Settings</strong> to say hello to the world.
  </p>
  <div class="...">...</div>
</div>

<!-- good - prefer semantic classes used accurately -->
<section class="...">
  <p>
    Simply visit your <span class="gl-font-bold">Settings</span> to say hello to the world.
  </p>
  <footer class="...">...</footer>
</section>

Buttons

Button type

Button tags requires a type attribute according to the W3C HTML specification. 

// bad
<button></button>

// good
<button type="button"></button>

Blank target

Arbitrarily opening links in a new tab is not recommended, so refer to the Pajamas guidelines on links when considering adding target="_blank" to links.

When using target="_blank" with a tags, you must also add the rel="noopener noreferrer" attribute. This prevents a security vulnerability documented by JitBit.

When using gl-link, using target="_blank" is sufficient as it automatically adds rel="noopener noreferrer" to the link. 

// bad
<a href="url" target="_blank"></a>

// good
<a href="url" target="_blank" rel="noopener noreferrer"></a>

// good
<gl-link href="url" target="_blank"></gl-link>

Do not use fake links. Use a button tag if a link only invokes JavaScript click event handlers, which is more semantic. 

// bad
<a class="js-do-something" href="#"></a>

// good
<button class="js-do-something" type="button"></button>