Suppose that your custom JS file is under webwb. You can add JS file in the harness (under "Scripts & styles" tab) where your button section resides. Configure the button click action as 'Run Script' to invoke the function defined in your custom JS file. 

Hi,

Please check below link. it might helpful.

https://collaborate.pega.com/question/click-button-using-run-script

Thanks

In Addition to Susan's comment, you can also add the script in the HTML fragment 'UserWorkForm' and then call the function by configuring "Run Script" on click of the button.

If you want to use this JS application wide then please check the below dicussion:

https://collaborate.pega.com/question/best-place-include-javascript-function

Hi All, 

This seems to be a question from Robotic Automation. If I am correct, please tag it and remove other tags so that it can be routed to the right team.