pop-up error message --V8

I want to add a condition in the input form of the data loading activity. If I drag and drop the activity without configuring it, an error message such as "configure the activity" should pop up when I save the workflow. Similarly, in the advance tab of the activity in the comment session, if I add a comment, an error message should pop up while saving the workflow. Can someone share the syntax and where this code should be added?

Thanks