Input Mask:
The input mask you want to use to control the data the user inputs into the object. Input masks let you pre-format the user's response a bit with "guide" characters, and help prevent errors by performing keystroke validation. You can click the select button to display a list of sample input masks.

One of the sample input masks available is a telephone number. It appears in the list as (###) ###-####.
The "#" character in the input mask is a special digit placeholder (0-9). For every # in the input mask, the user will only be able to enter a digit between 0 and 9. At runtime, the user will only be able to enter 10 numeric characters and will appear as a formatted telephone number such as (204) 946-0263.

You can also include alphabetic characters in an input mask. For example, one of the sample input masks is ?#? #?# used to represent a Canadian postal code. The "?" character in the input mask is a special alphabetic placeholder (a-Z). For every ? in the input mask, the user will only be able to enter a letter from a to Z. For example, R3B 0R3 is one valid postal code that the user could enter. The mask would prevent the user from entering two sequential alphabetic characters or numbers.