Masked textbox

The Masked textbox field lets users enter text, numbers, or symbols in a predefined format set by the form creator. It looks like a standard textbox, with placeholder values that visually show the mask’s structure: useful for formats like postal codes, phone numbers, or email addresses.

Property	Description
Type (Simple / Email)	Defines the field’s behavior.
Mask	A pattern of characters that determines which input is valid. Only applies when Type is Simple.

Mask characters

Character	Meaning
0	Required digit (0–9)
9	Optional digit or space
#	Optional digit or space, allows + or -
L	Required letter (a–z or A–Z)
C	Optional letter or space
A	Required alphanumeric character
a	Optional alphanumeric character

When Type is Email, the mask is ignored and standard email formatting rules are enforced instead.

Errors

Message	Meaning	Solution
The input value does not match the format.	The user’s input doesn’t follow the defined mask.	Adjust the mask, or clarify the expected format for the user.

Tips

• Don’t build your own email mask: use the built-in Email type, which already enforces correct formatting.
• Be intentional with optional mask characters (like a): they can let incomplete input through, for example 1234 instead of 1234AA for a postal code.
• Give users clear instructions when a mask enforces a strict pattern.