The FORMATTEFIELD is a field component which is applying certain formatting and checking rules when the user keys in data. The rules depend on the data type (attribute FORMAT), there may be additional information in the attribute FORMATMASK.

Example: you may use the FORMAT "bigdecimal" for checking the input to be a decimal number. By defining FORMATMASK "dec2" you ensure that the formatting will always render 2 decimal digits (i.e. "20,00" instead of "20") - and that user input with more than 2 digits will automatically rounded.