---
sourceDocument: Australia ServiceNow AI Platform Capabilities
sourceDocumentLink: https://www.servicenow.com/docs/r/servicenow-platform

 Release :

    - australia

ft:locale :

    - en-US

ft:publication_title :

    - Australia ServiceNow AI Platform Capabilities

ft:clusterId :

    - platcap

bundleId :

    - platcap

workflow :

    - Platform


---

# Service Catalog variable attributes

# Service Catalog variable attributes {#ariaid-title1}

* Release version: Australia
* 
* Updated March 12, 2026
* 
* ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 3 minutes to read

There are a few Service Catalog variables support specific attributes to
define the behavior and restrictions for variables.
In the Catalog variable form, under the Type Specifications tab, you
can specify the variable attributes in the Variable attributes
field.  
Note:  
* You can enter multiple attributes for a variable type by separating each with a comma.
* You can enter multiple values for an attribute by separating each with a semicolon.
* If you don't see the Variable attributes field, enable the Show attributes when Type is One of Certain Values UI policy.
* Pre-selected values are not cleared automatically when the dependent variable value changes when using an attribute or reference qualifier. Create a client script to clear the values based on your needs and the needs of your customer.
{#variable-attributes__ul_fjs_mwh_bmb}

## Variable attributes {#variable-attributes__section_wlf_1hz_dmb}

allowed_extensions

:   Specifies a list of allowed file types. For example,
    <kbd class="ph userinput">allowed_extensions=txt;pdf</kbd>.

    Applicable variables: Attachment

barcode

:   Specifies if the barcode can be scanned using the mobile camera for identifying a
    variable value of a catalog item. For example,
    <kbd class="ph userinput">barcode=true</kbd>.

    Applicable variables: Single Line Text

max_file_size

:   Specifies the maximum file size in MB. For example,
    <kbd class="ph userinput">max_file_size=2</kbd>.

    Applicable variables: Attachment

glide_list

:   Changes the list collector interface from slushbucket to glide list.

    Applicable variables: List collector

is_searchable_choice

:   If set to true, enables you to search for and select the required value for the variable. For example, <kbd class="ph userinput">is_searchable_choice=true</kbd>.

    Note:  
    * For Lookup select box, a default value is available at the page load itself.
    * This attribute is not applicable in Service Portal.
    {#variable-attributes__ul_p4t_vjd_t2b} Applicable variables: Lookup select box, Select box

max_length

:   Sets the maximum number of characters allowed in the field. By default, the field
    accepts long strings of text, several thousand characters. Set the
    max_length attribute as appropriate for the information that
    the variable is collecting. For example, to allow for entry of an address, set
    <kbd class="ph userinput">max_length=200</kbd>, or other appropriate length.

    Applicable variables: Single-line text, Wide single-line text

max_unit

:   Sets the maximum unit of time for the duration. Possible values are
    <kbd class="ph userinput">max_unit=days</kbd>,<kbd class="ph userinput">max_unit=hours</kbd>,<kbd class="ph userinput">max_unit=minutes</kbd>,
    and <kbd class="ph userinput">max_unit=seconds</kbd>.

    For example, if
    <kbd class="ph userinput">max_unit=minutes</kbd>, the duration is displayed in minutes and
    seconds. In this case, a duration of 2 days 3 hours 5 minutes 15 seconds is displayed
    as 3065 minutes 15 seconds.
    Applicable variables: Duration

no_filter

:   Hides the filter fields that appear above a list collector.

    Applicable variables: List collector

ref_ac_columns
:   Specifies the columns with display values that appear in an auto-completion list in addition to the name. Separate column names with a semicolon. For example,
    <kbd class="ph userinput">ref_ac_columns=user_name;email;sys_created_on</kbd> allows auto-complete to match text from the user_name, email, and sys_created_on columns.

    Applicable variables: Reference,
    Requested For.

ref_ac_order_by

:   Specifies the column that is used to sort the auto-completion list. For example,
    <kbd class="ph userinput">ref_ac_order_by=name</kbd> sorts the auto-completion choices
    alphabetically by name.

    Applicable variables: Reference

ref_auto_completer

:   Specifies the name of a JavaScript class (client-side) that creates the list for
    auto-completion choices. Valid class values include:

    * AJAXReferenceCompleter: Displays matching auto-complete choices as a drop-down list. The list only displays the display value column of the reference table. If there is no other auto-completion class specified, reference fields automatically use this class.
    * AJAXTableCompleter: Displays matching auto-complete choices as rows in a table. The table displays the display value column of the reference table and any columns listed in the ref_ac_columns attribute.
    * AJAXReferenceChoice: Displays matching auto-complete choices as a drop-down list. The list only displays the display value column of the reference table. The list only displays up to 25 matching choices. If there are more than 25 auto-complete choices, the reference field instead displays the choices with the AJAXTableCompleter class.
    {#variable-attributes__ul_gjv_qy2_cz}Applicable variables: Reference

ref_qual_elements

:   A list of fields to be sent back to the server to get an updated
    reference.

Applicable variables: Lookup multiple choice, Lookup select box, List Collector.  
Important:  
Attribute behavior is specific to the service catalog desktop.
**Related tasks**   

* [Define help information for a service catalog variable](https://www.servicenow.com/docs/IZih9~y2eQ~s5cX2pRrrmQ "Enter help information for a variable to help users determine what info they must provide for a service catalog variable.")
* [Define a question choice for a variable](https://www.servicenow.com/docs/LstsClDdQUZ2YkhSt4D4vw "Define a question choice for a variable with service catalog.")