This sample demonstrates masked custom format WebInput feature for social security number.

When you create an input mask, you can use special characters to require that certain data be entered (for example, the area code for a phone number) and that other data be optional (such as a telephone extension). These characters specify the type of data, such as a number or character, that you must enter for each character in the input mask.When you type data in a field for which you've defined an input mask, the data is always entered in Overtype mode. If you use the BACKSPACE key to delete a character, the character is replaced by a PromptChar character.

Supported masking character.

9 - Digit or space (entry not required, plus and minus signs not allowed).
# - Digit or space (entry not required; spaces are displayed as blanks while in Edit mode, but blanks are removed when data is saved; plus and minus signs allowed).
L - Letter (A to Z, entry required).
? - Letter (A to Z, entry optional).
A - Letter or digit (entry required).
a - Letter or digit (entry optional).
& - Any character or a space (entry required).
C - Any character or a space (entry optional).
. , : ; - / - Decimal placeholder and thousand, date, and time separators (separator: A character that separates units of text or numbers.) . (The actual character used depends on the settings in the Regional Settings Properties dialog box in Windows Control Panel).
< - Causes all character to be converted to lowercase.
> - Causes all character to be converted to uppercase.
Other character - display as literal character.