Customizing CSS Values with HTML5 Data Attributes

In the realm of web development, the possibility of utilizing HTML5 data attributes to modify CSS values has sparked curiosity. This technique mimics the way CSS content can be altered through content properties.

Exploring the HTML5 Data Attribute Approach

Consider the following HTML and CSS snippet:

div { width: attr(data-width); }

Current Implementation Limitations

At the time of writing, this approach does not function as intended. The browser interprets the data-width attribute as a string, rather than a numerical value for width.

Upcoming Feature: Custom Properties

However, the CSS Values specification anticipates this feature. The attr() notation allows CSS to access the value of the specified data attribute.

div { width: attr(data-width); }

Implementation Status

Unfortunately, this feature is still under development and not fully supported by major browsers.

Alternative for Pseudo-Elements

While the ability to set CSS values directly isn't yet available, you can leverage pseudo-elements to manipulate content:

::after {
  content: attr(data-width);
}
This technique allows you to display the value of the data-width attribute as the content of the pseudo-element.