CSS Form Pseudo-classes

With pseudo-classes, we can target specific states of form elements, such as when a user focuses on a field, enters invalid data, or when a field is required.

Basic pseudo-classes

The most common pseudo-classes include <:focus>, which applies when the field is active, <:required> for required fields, and <:disabled> for disabled fields.

The following simple example shows a basic form with required fields styled with pseudo-classes.

Advanced pseudo-classes

The <:invalid> pseudo-class is particularly useful when a user enters incorrect data, such as an invalid email address. <:hover> or <:checked> also provide many options to make forms more interactive.

This example shows how a field changes color for invalid input and how the focused field is highlighted.

Tips for pseudo-classes

Pseudo-classes can significantly improve user experience when used wisely.

• Always provide feedback for invalid input.
• Use visual cues, such as color changes, to indicate focus or errors.
• Do not overload the user with too many changes; feedback should be clear but not overwhelming.