1.1.0 • Public • Published

Pristine - Vanilla javascript form validation library


~4kb minified, ~2kb gzipped, no dependencies

Living demo

Some examples of use can be found here.


Include the javascript file in your html head or just before the closing body tag

<script src="dist/pristine.js"  type="text/javascript"></script>

Now create some form and validate

window.onload = function () {

    var form = document.getElementById("form1");

    // create the pristine instance
    var pristine = new Pristine(form);

    form.addEventListener('submit', function (e) {
       // check if the form is valid
       var valid = pristine.validate(); // returns true or false


That's it

It automatically validates required, min, max, minlength, maxlength attributes and the value of type attributes like email, number and more..

Pristine takes 3 parameters

  • form The form element

  • config An object containing the configuration. Default is bootstrap's configuration which is

let defaultConfig = {
    // class of the parent element where the error/success class is added
    classTo: 'form-group',
    errorClass: 'has-danger',
    successClass: 'has-success',
    // class of the parent element where error text element is appended
    errorTextParent: 'form-group',
    // type of element to create for the error text
    errorTextTag: 'div',
    // class of the error text element
    errorTextClass: 'text-help' 
  • live A boolean value indicating whether pristine should validate as you type, default is true


$ npm install pristinejs --save

Custom Validator

pristine.addValidator(nameOrElem, handler, errorMessage, priority, halt);

Add a custom validator to a field

var pristine = new Pristine(document.getElementById("form1"));

var elem = document.getElementById("email");

// A validator to check if the first letter is capitalized
pristine.addValidator(elem, function(value) {
    // here `this` refers to the respective input element
    if (value.length && value[0] === value[0].toUpperCase()){
        return true;
    return false;
}, "The first character must be capitalized", 2, false);

Add a global custom validator

// A validator to check if the input value is within a specified range
// Global validators must be added before creating the pristine instance

Pristine.addValidator("my-range", function(value, param1, param2) {
    // here `this` refers to the respective input element
    return parseInt(param1) <= value && value <= parseInt(param2)
}, "The value (${0}) must be between ${1} and ${2}", 5, false);

Now you can assign it to your inputs like this

<input type="text" class="form-control" data-pristine-my-range="10,30" />

Add custom error messages

<input required data-pristine-required-message="My custom message"/>

Add an attribute like data-pristine-<ValidatorName>-messagewith the custom message as value to show custom error messages. You can add custom messages like this for as many validators as you need. Here ValidatorName means required, email, min, max etc.

Built-in validators

Name Usage Description
required required or data-pristine-required Validates required fields
email type="email" or data-pristine-type="email" Validates email
number type="number" or data-pristine-type="number"
integer data-pristine-type="integer"
minlength minlength="10" or data-pristine-minlength="10"
maxlength maxlength="10" or data-pristine-maxlength="10"
min min="20" or data-pristine-min="20"
max max="100" or data-pristine-max="100"
pattern pattern="/[a-z]+$/i" or data-pristine-pattern="/[a-z]+$/i", \ must be escaped (replace with \\)
equals data-pristine-equals="#field-selector" Check that two fields are equal


Pristine(form, config, live)

Parameter Default Required? Description
form - The form element
config See above The config object
live true Whether pristine should validate as you type

pristine.validate(inputs, silent)
Validate the form or field(s)

Parameter Default Required? Description
inputs - When not given, full form is validated. inputs can be one DOM element or a collection of DOM elements returned by document.getElement..., document.querySelector... or even jquery dom
silent false Does not show error messages when silent is true

pristine.addValidator(elem, fn, msg, priority, halt)
Add a custom validator

Parameter Default Required? Description
elem - The dom element where validator is applied to.
fn - The function that validates the field. Value of the input field gets passed as the first parameter, and the attribute value (split using comma) as the subsequent parameters. For example, for <input data-pristine-my-validator="10,20,dhaka" value="myValue"/>, validator function get called like fn("myValue", 10, 20, "dhaka"). Inside the function this refers to the input element
message - The message to show when the validation fails. It supports simple templating. ${0} for the input's value, ${1} and so on are for the attribute values. For the above example, ${0} will get replaced by myValue, ${1} by 10, ${2} by 20, ${3} by dhaka. It can also be a function which should return the error string. The values and inputs are available as function arguments
priority 1 Priority of the validator function. The higher the value, the earlier it gets called when there are multiple validators on one field.
halt false Whether to halt validation on the current field after this validation. When true after validating the current validator, rest of the validators are ignored on the current field.

Pristine.addValidator(name, fn, msg, priority, halt)
Add a global custom validator

Parameter Default Required? Description
name - A string, the name of the validator, you can then use data-pristine-<NAME> attribute in form fields to apply this validator
.... - - Other parameters same as above

Get the errors of the form or a specific field

Parameter Default Required? Description
input - When input is given, it returns the errors of that input element, otherwise returns all errors of the form as an object, using input element as key and corresponding errors as value. validate() must be called before expecting this method to return correctly.

pristine.addError(input, error)
Add A custom error to an input element

Parameter Default Required? Description
input - The input element to which the error should be given
error - The error string

Set the global configuration

Parameter Default Required? Description
config - Set the default configuration globally to use in all forms.

Set the current locale globally

Parameter Default Required? Description
locale - Error messages on new Pristine forms will be displayed according to this locale

Pristine.addMessages(locale, messages)
Set the current locale globally

Parameter Default Required? Description
locale - The corresponding locale
messages - Object containing validator names as keys and error texts as values

Reset the errors in the form

Destroy the pristine object

The goal of this library is not to provide every possible type of validation and thus becoming a bloat. The goal is to provide most common types of validations and a neat way to add custom validators.



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