set field based on scriptParameter

trying to use eternal calendar file to set the date in a field. have a layout with calendar icon; click on it calendar layout pops up, select date neeeded, click submit button, adds the date to the date field, script works fine as is, a lot of else if statements with scriptparmeter vaules, issue everytime you add a date field have to add that to script. would like a way to use pattern count or something like that to get the field from the scriptparameter to determine which field to set based of that info, so when adding new fields do not have to add them to script just dynamically added.