WordPress Comment Form Placeholders

functions.php

/*
 *
 * Add Placeholders to Comment Forms
 * Keep in mind that if you want to kill the labels, the easiest way is use display:none in your stylesheet for the labels
 *
 */
add_filter( 'comment_form_default_fields', 'sabretooth_comment_placeholders' );

function sabretooth_comment_placeholders( $fields ) {
    $fields['author'] = str_replace(
        '<input',
        '<input placeholder="Full Name*"',
        $fields['author']
    );
    $fields['email'] = str_replace(
        '<input',
        '<input placeholder="Email*"',
        $fields['email']
    );
    $fields['url'] = str_replace(
        '<input',
        '<input placeholder="Website"',
        $fields['url']
    );
    return $fields;
}
  
/* Add Placehoder in comment Form Field (Comment) */
add_filter( 'comment_form_defaults', 'sabretooth_textarea_placeholder' );
  
function sabretooth_textarea_placeholder( $fields ) {
    $fields['comment_field'] = str_replace(
        '<textarea',
        '<textarea placeholder="Comment"',
        $fields['comment_field']
    );

	return $fields;
}