Custom Validation form

Hi,

i would like to validate a text tag in contact form 7, to validate an italian car plate, this is my RegExp in JavaScript:

 <script>
		
		function targaCheck(){
var targaRExp = /^(([a-zA-Z]{2}\d{3}[a-zA-Z]{2})|(([a-zA-Z]{2}|roma)(\d{5}|\d{6})))$/i;
var targa = document.getElementById("targa").value;

		if( targaRExp.test(targa) ) {
   alert("Correct");
}else {
   alert("Incorrect");
}
		}
		</script> 

To validate the contact form 7 i have to use “add_filter” in function.php of my WP site, but when i insert my code it doesn’t work. (this is an example of code)
https://contactform7.com/2015/03/28/custom-validation/

add_filter( 'wpcf7_validate_email*', 'custom_email_confirmation_validation_filter', 20, 2 );
 
function custom_email_confirmation_validation_filter( $result, $tag ) {
    $tag = new WPCF7_FormTag( $tag );
 
    if ( 'your-email-confirm' == $tag->name ) {
        $your_email = isset( $_POST['your-email'] ) ? trim( $_POST['your-email'] ) : '';
        $your_email_confirm = isset( $_POST['your-email-confirm'] ) ? trim( $_POST['your-email-confirm'] ) : '';
 
        if ( $your_email != $your_email_confirm ) {
            $result->invalidate( $tag, "Are you sure this is the correct address?" );
        }
    }
 
    return $result;
}

how can i do?

Please help me

Thanks!