Forms: Javas: Calculation script returns error before user finishes typing their entry

Hey all,

I'm relatively new to java. 

Question: Is there a code that functions like 'event.target'--e.g. triggers when user completes an entry, clicks away from the field--that can be used external to the field in which the event occurs? Specifically, in the calculation script of a hidden field.

I am writing numerous 'field validations' that display or hide fields ('error messages'). I can mod/copy this script into each field as an onBlur action, which effectively performs the 'validation' after the user clicks away. I can also paste it in each field as a validation script. This works fine enough. But it occurs to me it would be simpler if all the codes were consolidated in one place.

My idea is to consolidate all my scripts, including the 'field validations', into one hidden field, as a calculation script. 

Problem is: when I change event.target to the field name, the code calculates as soon as a field is entered, and calculates again after each character is entered. This is not desirable.

Here's the code i'm using in the calculation script below. The script functioned properly if internal1.value is replaced by event.target.value.