Required

Pseudo-class

:required

Selects form elements that have the required attribute.

Example

input:required {
  border-left: 3px solid red;
}

Specificity

0-1-0

Browser Support

All browsers

About the Required

The :required CSS selector belongs to the Pseudo-class category.Selects form elements that have the required attribute. Understanding CSS selector specificity and combinators is essential for writing maintainable stylesheets that behave predictably.

The specificity of this selector is 0-1-0. CSS specificity determines which styles are applied when multiple rules target the same element. Higher specificity values take precedence. The specificity hierarchy from lowest to highest is: universal (*) → type/element → class/attribute/pseudo-class → ID → inline styles → !important.

Browser support for Required is: All browsers. When using newer CSS selectors like :has(), :is(), or CSS nesting, consider providing fallback styles for older browsers. Use @supports to progressively enhance your stylesheets with modern features while maintaining backward compatibility.

Related Selectors

:optional :valid :invalid