I need to be able to validate data that the user enters into a prompt box. This could either be as they enter it and click ok or after once it has been stored into a variable. Is this possible at all. Also this is my code at the moment forename=prompt("Please enter Employees Forename.",""); surname=prompt("Please enter Employees surname.",""); employeeno=prompt("Please enter Employees No.",""); hoursworked=prompt("Please enter hours worked.",""); payrate=prompt("Please enter pay rate per hour.",""); nino=prompt("Please enter National Insurance Number.",""); type=prompt("Please enter F for full time or P for part time.",""); Code (markup): I need each of the validating to numbers, text, certain lengh etc Thanks