$wp_upload_dir = wp_upload_dir();
    ?>
    <tr class="form-field">
        <th scope="row" valign="top"><label for="wh_mobile_image"><?php _e('Mobile image', 'wh'); ?></label></th>
        <td>
            <script type="text/javascript">
                function uploadFile(field, baseDir) {
                    console.log(baseDir)
                    let mobile_image = field.files[0]
                    let formData = new FormData( $("#mobile_upload")[0] )
                    formData.append("mobile_upload", mobile_image)
                    formData.append("baseDir", baseDir)

                    $.ajax({
                        url: 'upload-mobile.php',
                        type: 'post',
                        data: formData,
                        contentType: false,
                        processData: false
                    })
                    .done(function(data) {
                        console.log(data)
                    })
                }
            </script>

                <form id="mobile_upload" enctype="multipart/form-data" method="post" >
                <input type="file" onchange="uploadFile(this, '<?php echo $wp_upload_dir["basedir"] ?>')" name="wh_mobile_image" id="wh_mobile_image" value="<?php echo esc_attr($wh_mobile_image) ? esc_attr($wh_mobile_image) : ''; ?>">
                </form>
        </td>
    </tr>