Regular expressions can be used in the advanced profile fields/custom profile fields.

The input mask is important for your forum's security. Validating the input from a user can help ensure that data is not used in a way you do not expect. We have provided some simple regular expressions as hints.

"[A-Za-z]+" - Match all upper and lower case alphabet characters. "[0-9]+" - Match all numeric characters. "[A-Za-z0-9]{7}" - Match all upper and lower case alphabet and numeric characters seven times. "[^0-9]?" - Forbid any number from being matched. "^([A-Fa-f0-9]{3}|[A-Fa-f0-9]{6})$" - Only allow 3 or 6 character hexcodes.

Additionally, special metacharacters ?+*^$ and {xx} can be defined. ? - None or one match of previous expression. + - One or more of previous expression.

• - None or more of previous expression.

{xx} - An exact number from previous expression. {xx,} - An exact number or more from previous expression. {,xx} - An exact number or less from previous expression. {xx,yy} - An exact match between the two numbers from previous expression. ^ - Start of string. $ - End of string. \ - Escapes the next character.

More information and advanced techniques may be found on the internet.