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readonly( mixed $readonly, mixed $current = true, bool $echo = true )

Outputs the HTML readonly attribute.

Compares the first two arguments and if identical marks as readonly

$readonly

(mixed) (Required) One of the values to compare

$current

(mixed) (Optional) (true) The other value to compare if not just true

Default value: true

$echo

(bool) (Optional) Whether to echo or just return the string

Default value: true

(string) HTML attribute or empty string

function readonly( $readonly, $current = true, $echo = true ) {
	return __checked_selected_helper( $readonly, $current, $echo, 'readonly' );
}

Uses	Description
wp-includes/general-template.php: __checked_selected_helper()	Private helper function for checked, selected, disabled and readonly.

Version	Description
4.9.0	Introduced.

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Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/readonly