MAKING FORM FIELD AUTO TAB

So I have this PDF form with several fields. The form I am working with is being used as a vehicle check-in sheet and the area in question is the Vehicle Identification Number (VIN) section. A Vin is 17 digits and I have 17 different fields limited to a max count of 1 the problem is when I use a standard JavaScript code in the document of

function goNext(item, event, cName)

{AFNumber_Keystroke(0, 0, 0, 0, "",TRUE);

if (event.rc &&

AFMergeChange(event).length ==event.target.

charLimit)

item.getField(cName).setFocus();

}

and in the field properties I have selected under the format tab

Format category Custom

Custom Keystroke Script: goNext(this, event, "Vin2");

My problem is I can only use numerical digits and if I try to use a normal vin such as 1cg745bs743825167 it won’t let me use the letters. Also I am trying to figure out how to click on the first form field for the first character of the vin and then press Cntrl+V to paste the VIN and it won’t let me does anyone have any pointers on how to make these two things happen?

[Asking in the correct forum helps... Moved from non-technical Forum Lounge to specific Program forum... Mod]