FFCustomReCaptcha.php

add_action('recaptcha_custom_function', 'recaptcha_custom_function_callback', 10, 1 );
function recaptcha_custom_function_callback( $form) {
	echo '
        <script type="text/javascript">
		jQuery( document ).ready(function() {
			jQuery(".ff-btn-submit").attr("disabled", "true");
		});
		function enableBtn(){
			jQuery(".ff-btn-submit").removeAttr("disabled");
		}
		</script>';
    echo "<script src='https://www.google.com/recaptcha/api.js' async defer ></script>";
    ?> 
    <div class="ff-el-group" data-name="recaptcha">
        <div class="ff-el-input--content">
			<div class="ff-el-recaptcha g-recaptcha" data-sitekey="6LcpRNoZAAAAAB5CPHvzM-n-RfVvyFojnbxjTNOB" data-callback="enableBtn"></div>
	    </div>
    </div>
    <?php
}