The native HTML5 validation feature is not enough.
We also recommend you use a JavaScript library to extend and enhance the default form validation functionalities for better user experiences on modern web design.
In this post, you’ll find a list of the 10 best and most downloaded JavaScript Form Validation libraries (without any 3rd dependencies such as jQuery) to validate your HTML form with custom error messages, CSS styles, validation rules, and more. Enjoy.
Originally Published Feb 10, 2018, updated Jan 13 2025
1. Just-validate
Just-validate is a dependency-free, HTML5 data attribute based form validation that supports both client side and server side form validation. Validation rules are fully customizable via JavaScript. Compatible with Bootstrap framework.
2. Regex Based Form Validator For Bootstrap 5
A script that demonstrates how to validate form fields in your Bootstrap 5 project by using custom Regex.
3. Native Validator
A vanilla JavaScript-powered form validation library for the latest bootstrap framework, without jQuery dependency.
4. Pristine
Pristine is a lightweight vanilla JavaScript form validation library which works with the native HTML5 attributes and allows you to create your own validators of course.
5. Validator.js
A fast, cross-browser, user-friendly, highly customizable form validator that works with the native HTML5 input types: text, email, url, date, etc.
6. Bouncer.js
The Bouncer.js JavaScript library is created to extend the native HTML5 form validation that enables the customizable form validation on the form fields.
7. Beginner-Friendly JavaScript Form Validation Library – Trivule
A JavaScript library designed to simplify form validation. It’s perfect for both beginners and experienced developers.
8. validator.js
Lightweight JavaScript form validation, that had minimal configuration and felt natural to use. No dependencies, support UMD.
9. OctaValidate
An important aspect of user experience in modern websites. Good validation helps to improve conversions, especially in a contact form. In many cases, when the user encounters a validation error page, they will lose interest and not complete the form — even if they are interested in your products and services.
10. Vanilla JavaScript Form Validator For Bootstrap 5/4/3 Framework
A vanilla JavaScript plugin that adds extensible form validation functionalities to your Bootstrap project without third-party JS libraries like jQuery.
More Resources:
Looking for more JavaScript solutions to validate form fields on modern web applications? Here are some resources you might find useful: