Need help on scripting

Folks, I could use some assistance with some script i am trying to develop. I have a form set-up with several different input boxes / data entry fields. On of the fields is titled "Phase" for the sake of this example the other field is titled "Area". The gist of what I am trying to do is as follows. When the data entered into Phase equals Phase 5, I want an alert to pop up in the Area field indicating that the Area field needs to be completed. The Area field only needs to be completed when Phase equals Phase 5. So, what I did was write the script below using an "on user input" action. the script is within the Area field not the Phase field. Unfortunately the script crashes out at the last bracket. I obviously am doing something wrong, but can't quite figure it out.

Thanks for any help.

if (input.Phase == "Phase 5")
{

alert "test"

}
rindge