Last four ssn

It should be noted that the validation for the special SSN format does not exclude values where the first 3 digits, region, are "000" or "666" which values are not used in issuing SSNs. Also the last 4 digits, serial number, cannot be "0000".

Since the entry of the SSN could include the separator characters "-", ".", " ", or none one cannot easily use the substr or substring properties of a string unless all possible combinations of the numbers and special characters are teste. Fortunately JavaScript has implemented the Regular Expression object so one can test the inputted string and retrieve only the numeric digits.

The following script used in the on blur action can copy the last 4 digits of the SSN from the input field to a second field. You will need to adjust the field name to match your form.

// 0n blur action to copy last 4 of SSN to another field;

var cResultField = "SSN2"; // name of other field;

if(event.value != "")

{

// use Regular Expression object to extract last 4 digits of SSN ignoring any separator characters;

if(/^(\d{3})[-. ](\d{2})[-. ](\d{4})$/.test(event.value))

{

  this.getField(cResultField).value = RegExp.$3;

} // end if RegExp test true;

} // end event value not null;

// end on blur action;