Can a web-based GIS system's appian interface be modified to include javascript in order to retrieve data from it

[pushpa1997]

Users can currently enter information about a specific parcel of property, including its lot number, street location, postal zip code, and the local government jurisdiction it is located under, into an Appian interface.
But, all of this data is accessible through our web-based GIS [Geographical Information System], which enables users to search a map in a manner that is fundamentally comparable to that of Google Maps. Currently, users use another browser window to look at all the information in our GIS system before typing the values they see on the GIS mapping tool onto the screen supplied by our appian interface while both windows are open.
We would like to be able to have the GIS system automatically fill the fields in our appian interface. Making an API call to the GIS system is necessary to accomplish this. If I were implementing this in a standard web application, I would use javascript to call the distant GIS system and then fill in the necessary information. Can I add javascript to the Appian interface so that I may change the values of fields there? In order to store the data from the looked-up fields in our Appian-based application, I merely want to programmatically fill in the fields in the Appian interface on-screen. The users can then select whether or not to submit the form.