This simple PHP snippet allows users to enter URLs starting with "www." in the website field of Gravity Forms without requiring "https://". It modifies the validation logic to accept "www." by automatically prepending "https://" for validation. Ideal for WordPress developers looking to customize form URL validation.

allow-www-in-website-field-validation-gravity-forms.php

<?php
/**
 * Allow URLs starting with "www." in Gravity Forms website field validation.
 *
 * This snippet enables users to enter URLs like "www.example.com"
 * without needing to type "https://". It prepends "https://" internally
 * for validation purposes.
 *
 * @author Faisal Ahammad <me@faisalahammad.com>
 */

add_filter( 'gform_field_validation', function( $result, $value, $form, $field ) {
    if ( $field->type !== 'website' ) {
        return $result;
    }

    if ( ! $result['is_valid'] && preg_match( '/^www\./i', trim( $value ) ) ) {
        $url_with_protocol = 'https://' . trim( $value );

        if ( GFCommon::is_valid_url( $url_with_protocol ) ) {
            $result['is_valid'] = true;
            $result['message']  = '';
        }
    }

    return $result;
}, 10, 4 );

Ticket: https://community.gravityforms.com/t/allowing-www-in-website-field/20028