Validators 

Alphanumeric 

This validator checks whether the field contains an alphanumeric string. "Alphanumeric" means a combination of alphabetic and numeric characters. No special characters can be entered, only characters from [A-Z] and [0-9]. The settings of the validator are as follows:

• Custom error message: Custom error message that will be shown if the validator fails.

The validator is available for the following form elements:

• "Text"
• "Textarea"
• "Password"
• "Advanced password"

String length 

This validator uses minimum and maximum values to check how many characters can be entered. The settings of the validator are as follows:

• Minimum: Minimum amount of characters the field can contain.
• Maximum: Maximum amount of characters the field can contain.
• Custom error message: Custom error message that will be shown if the validator fails.

The validator is available for the following form elements:

• "Text"
• "Textarea"
• "Password"
• "Advanced password"

Email 

This validator checks whether an entered value is a valid email address. International characters and multiple occurrences of the @ sign are allowed by default. The settings of the validator are as follows:

• Custom error message: Custom error message that will be shown if the validation fails.

The validator is available for the following form elements:

• "Text"
• "Email address" (validator is automatically active)
• "Password"
• "Advanced password"

Integer number 

The validator checks whether an entered value is a valid integer. Numbers with commas are not allowed. The settings of the validator are as follows:

• Custom error message: Custom error message that will be shown if the validation fails.

The validator is available for the following form elements:

• "Text"
• "Textarea"
• "Password"
• "Advanced password"

Floating-point number 

The validator checks whether an entered value is a valid floating-point number. Only numbers with commas can be entered. The settings of the validator are as follows:

• Custom error message: Custom error message that will be shown if the validation fails.

The validator is available for the following form elements:

• "Text"
• "Textarea"
• "Password"
• "Advanced password"

Number 

The validator checks whether the entered value is a valid number. Numbers with commas are not allowed. The settings of the validator are as follows:

• Custom error message: Custom error message that will be shown if the validation fails.

The validator is available for the following form elements:

• "Number" (validator is automatically active)

Number range 

The validator checks if an entered number is within a specified number range. The settings of the validator are as follows:

• Minimum: The minimum value that can be accepted.
• Maximum: The maximum value that can be accepted.
• Custom error message: Custom error message that will be shown if the validation fails.

The validator is available for the following form elements:

• "Text"
• "Textarea"
• "Password"
• "Advanced password"
• "Number"

Regular expression 

The validator checks whether an entered value matches a specific regular expression. The settings of the validator are as follows:

• Regular expression: The regular expression used for validation.
• Custom error message: Custom error message that will be shown if the validation fails.

Imagine that you want users to specify a domain name. The resulting value of the field should contain only the domain, for example, "docs.typo3.org" instead of "https://docs.typo3.org". The regular expression for this would be /^[a-z]+.[a-z]+.[a-z]$/.

The validator is available for the following form elements:

• "Text"
• "Textarea"
• "Password"
• "Advanced password"
• "Telephone number"
• "URL"

Date range 

This validator checks whether an entered value is within a specific date range. The range can be defined by specifying a minimum and/ or maximum date. The settings of the validator are as follows:

• Minimum date: The beginning of the date range.
• Maximum date: The end of the date range.
• Custom error message: Custom error message that will be shown if the validation fails.

For Minimum date and Maximum date, select one of these options:

• No value: The range has no limit on this side.
• Today: The current date at the time the form is displayed or submitted.
• Absolute date: A fixed date that you select in a date picker.
• Relative date: A date relative to the current day. Select "past" or "future", enter an amount, and select days, weeks, months, or years.
• Custom relative expression: Enter any other relative date expression, for example "+1 month +3 days".

TYPO3 calculates relative dates each time the form is displayed or submitted. For example, set Maximum date to Relative date, "past", "18", and "Years". Users must then enter a date of birth at least 18 years ago. You can combine an absolute date with a relative date. See also the configuration of the date range validator.

The validator is available for the following form elements:

• "Date"

Number of submitted values 

The validator checks whether an entered value contains a specific number of elements. The settings of the validator are as follows:

• Minimum: The minimum number of values submitted.
• Maximum: The maximum number of submitted values.
• Custom error message: Custom error message that will be shown if the validation fails.

The validator is available for the following form elements:

• "Multi checkbox"
• "Multi select"

File size 

The validator checks the file size of a file resource. The settings of the validator are as follows:

• Minimum: The minimum acceptable file size (default: 0B).
• Maximum: The maximum acceptable file size (default: 10M).

Use the format B | K | M | G (byte | kilobyte | megabyte | gigabyte) when entering file sizes. For example: 10M means 10 megabytes. Please note that the maximum file size also depends on the settings of your server environment.

The validator is available for the following form elements:

• File upload
• Image upload

Number of files 

The validator checks how many files a user uploads in one field. Use it together with the setting Allow multiple upload. In the Inspector, the validator is shown as "Number of uploaded files". The settings of the validator are as follows:

• Minimum: The minimum number of uploaded files.
• Maximum: The maximum number of uploaded files.

The validator is available for the following form elements:

• File upload
• Image upload

See also the configuration of the number of submitted values validator.

Date/ Time 

The validator checks if an entered value is a valid date and/ or time. The settings of the validator are as follows:

• Custom error message: Custom error message that will be shown if the validation fails.