regexp validator

Check if the value matches given JavaScript regular expression


Using with form field

The HTML attributes are used to set the validator options via the Declarative plugin

Name HTML attribute Type Description
flags data-fv-regexp___flags String

If specified, flags can have any combination of JavaScript regular expression flags such as:

  • g: global match
  • i: ignore case
  • m: multiple line
message data-fv-regexp___message String The error message
regexp* data-fv-regexp___regexp or pattern String or RegExp The JavaScript regular expression


Look at the Alias plugin if you want to have multiple regular expressions on the same field

Using with JavaScript module

// You might need to change the importing path
import regexp from 'formvalidation/validators/regexp';

const result = regexp().validate({
    value: ...,
    options: {
        flags: ...,
        message: ...,
        regexp: ...,
result is an object of
    valid: true or false,
    message: The error message

Use a correct pattern

If the validator still pass when the field value doesn't match the pattern, please ensure you use a correct pattern. Here are some check lists:

  1. Is the pattern wrapped between ^ and $?

    For example, if a field must be 5 digits number, then ^\d5 (no $ at the end) is wrong pattern. ^\d5$ is right one.

  2. Does the pattern work with external services?

    You can use the following services to test the regular expression:

Useful patterns

The following table collects some useful patterns:

Description Pattern
SSN (Social Security Numbers) ^(?!000|666)(?:[0-6][0-9]2|7(?:[0-6][0-9]|7[0-2]))-(?!00)[0-9]2-(?!0000)[0-9]4$
Traditional time in 12-hour format
  • without seconds (hh:mm): ^(1[0-2]|0?[1-9]):([0-5]?[0-9])$
  • with seconds (hh:mm:ss): ^(1[0-2]|0?[1-9]):([0-5]?[0-9]):([0-5]?[0-9])$
Traditional time in 24-hour format
  • without seconds (hh:mm): ^(2[0-3]|[01]?[0-9]):([0-5]?[0-9])$
  • with seconds (hh:mm:ss): ^(2[0-3]|[01]?[0-9]):([0-5]?[0-9]):([0-5]?[0-9])$
Numbers in a particular range
  • Range of 1-12 (hour, month): ^(1[0-2]|[1-9])$
  • Range of 1-24 (hour): ^(2[0-4]|1[0-9]|[1-9])$
  • Range of 0-59 (minute, second): ^[1-5]?[0-9]$
  • Range of 1-31 (day of month): ^(3[01]|[12][0-9]|[1-9])$
  • Range of 0-100 (percentage): ^(100|[1-9]?[0-9])$

Basic Example

In the following form, user is asked to enter the full name which alphabetical characters and spaces only.

HTML5 Example

When the Declarative plugin is used, the regexp validator will be turned on automatically if the input uses HTML 5 pattern attribute.

Validating social account URL

Instead of using the uri validator, this example uses the regexp validator to validate Facebook account URL, such as http(s)://

Module Example

The following snippet shows how to use the regexp validator with JavaScript module:

// You might need to change the importing path
import regexp from 'formvalidation/validators/regexp';

const res1 = regexp().validate({
    value: 'Ms',
    options: {
        regexp: /^[A-Zs]+$/,
        message: 'The input is not valid',
// res1.valid === false

const res2 = regexp().validate({
    value: 'form VALIDATION',
    options: {
        regexp: '^[A-Z\s]+$',
        flags: 'i',
        message: 'The input is not valid',
// res2.valid === true