Little fix to get Oscommerce dropdown using (tep_draw_pull_down_menu) visible or not depending on selection from another. dropdown

I am using Oscommerce for a website. In the admin section I need to have one dropdown and a text field to be displayed only when an specific option is selected from another dropdown. This is the code: $contents[] = array('text' => TEXT_ALERT_TYPE . ': <br />' . tep_draw_pull_down_menu('alert_type', $alert_type_array, $aInfo->alert_type,)); $contents[] = array('text' => TEXT_CHENGE_TYPE . ': <br />' . tep_draw_pull_down_menu('change_type', $change_type_array, $aInfo->change_type)); $contents[] = array('text' => TEXT_VALUE . ': <br />' . tep_draw_input_field('value', $aInfo->value)); I need to have "change_type" and "value" fields displayed only when "between_max_and_min" is selected in dropdown for "alert_type".