Gravity Forms Hook - 插入 jQuery（未定义错误）

Question

我试图将一些 jQuery 插入重力表单挂钩 (gform_post_paging) 以禁用多页表单上的上一个按钮。我收到一个 jQuery 未定义错误。我确定正在调用 jQuery，所以不确定发生了什么。如果这很重要，多页表单正在使用 ajax。

我的代码：

add_action( 'gform_post_paging_4', 'alert_user', 10, 3 );
function alert_user( $form, $source_page_number, $current_page_number ) {
        if ( $current_page_number == 2 ) {

            $to = $_POST['input_3'];
            $subject = ot_get_option( 'consultant_verification_email_subject' );
            $headers = array('Content-Type: text/html; charset=UTF-8');
            // get the email content from option tree.  We are setting a static value for the code.
            // if this code needs to change, it should be updated in gravity forms for now
            // @todo: we could randomize this value if we want then check the value using jquery
            $body = ot_get_option( 'consultant_verification_email' );

            wp_mail( $to, $subject, $body, $headers );

            ?>

            <script type="text/javascript">
                alert( 'An email was sent to <?php echo $to; ?> with your verification code.  Please enter this code to continue.  Should you have failed to receive this email, please click the previous button, confirm your email, and click next again.  Should you continue to encounter difficulty, please contact us.' );
            </script>

            <?php
        } else if ( $current_page_number == 3 ) {
            // disable the previous button so user cant go through verification steps again
            ?>
            <script type="text/javascript">
                jQuery(".gform_previous_button").prop("disabled",true);
            </script>
            <?
        }
    }

Answer 1

可能同样易于使用 vanilla js：

    <script type="text/javascript">
        document.getElementsByClassName('gform_previous_button')[0].disabled = true;
    </script>

同样简单！