Changing Drop Down Menu on the fly via other form actions

[PTS]

Hey everyone, I'm stuck with a project I'm working on. I have database which collects a lot of information. However, for the sake of ease, lets say the database consists of five fields.

 

1. status (dropdown)

2. action1 (text field)

3. action2 (text field)

4. action3 (text field)

5. action4 (text field)

 

When I update a row of data via a form I have, I want the dropdown status field to be updated depending on whether or not the other text fields are filled in. For example, if text field 1 is filled in, I what the status drop down menu change to 1, If status 2 is filled in, the drop down would be moved to 2. And so on. I don't want the user to have to change the drop down menu himself, I'm trying to see if this can be done on the fly if this can be done on the fly.

 

The only other note of importance would be the user would never fill in "action4" field without all the other "action" fields below being already filled in and locked out. So if action1 is already filled in when a user is updating, the user can only update "action2". Hopefully that makes some sense.