function author($field, $value, $fieldinfo) {
        if($value=='') $value = !empty($fieldinfo['default_value'])?$fieldinfo['default_value']:'';
        $require = $fieldinfo['min_length']  ? 'required' : '';
        $pattern = $fieldinfo['pattern'] ?$fieldinfo['pattern']:'';
        $errortips = $fieldinfo['error_tips'] ?$fieldinfo['error_tips']:'';
        $form_attribute = $fieldinfo['form_attribute'] ?$fieldinfo['form_attribute']:'';
        $css = $fieldinfo['css'] ?$fieldinfo['css']:'';
        $string =  '<div class="mb-3 row '.$require.'">';
        $string .= '<label class="col-md-2 col-form-label">'.$fieldinfo['name'].'</label>';
        $string .= '<div class="col-md-10">';
        $string .= '<input type="text" name="info['.$field.']" value="'.$value.'"  data-pattern = "'.$pattern.'" data-errtips = "'.$errortips.'" autocomplete="off" class="form-control '.$require.'" '.$form_attribute.'   style="'.$css.'">';
        $string .= $fieldinfo['tips']?'<div class="text-muted  input-word-aux">提示：'.$fieldinfo['tips'].'</div>':'';
        $string .= '</div>';
        $string .= '</div>';
        return $string;
    }