How to validate Form fields before Open the Modal Propose Solution

[jay97]

Hello , 

I have declarative action Propose Solution which is implemented as UXF Client Action and it has already a one data resource event on it .  i want that before click on the button it should validate field on the form   How should I implemented it ?

what should i do that it should validate the form fields before open the modal ? 

The modal should only open if the 'Account', 'Contact', and 'Partner' fields are filled. Otherwise, prompt the user to complete these fields.

Please guide me on it thank you;