Validating a field only when a different field changes

[jberg416]

Is there any way to validate a field when the value of a different field changes?

 

Example:

I want my service tech to check a box for Type of Service before he is able to change the Service Status to Closed.  Right now I have the Type of Service field requiring validation but I really only need that box checked when the status changes to closed.  I don't want the person who creates the service to be required to check that box.  Is there a script or something I can write to make it do what I want.

 

"If Service Status = Closed, then validate "Type of Service."???

[webko]

Attach a script to the Service Status field that checks for the Type of Service having a value