Get red flag for a blank field when Adding a new project for example in the app

I developed an application for projects' inventory. I have "add new project" form. As for the form, is there any way to set a rule for users, when they submit a new project, for sure fill some fields and don't leave it blank? For example, if a "cost" field is empty, and they are submitting the form, that field turns red and flag for the user to fill it. Thanks!

Like this:

![](upload://pTWuXpeRcSOLh7u6aRGkhldObPS.png)

![](upload://dAcJfedFnrqpudgatv1IeygHROc.png)

Hi Kelson- Thanks for your comment. How can add JavaScript? 

Hi Elham, 

You can add some javascript to the form view that will prevent the form submission and loop through all of the fields checking if they are empty or not and adding custom CSS to the ones that are empty. 

If you need help with this don't hesitate to reach out

Best Regards, 

Kelson
kelson@ksensetech.com
http://www.ksensetech.com/knack/