Upgrading from v2? Read the migration guide
NFSFU234FormValidation reads the validation attributes already present on your forms—required, type, pattern, minlength, maxlength, min, max, step and more.
When native HTML validation isn't enough, extend it with one configuration object—or configure an entire website using the same API. Configure one form or an entire website using the same API.
$npm install @nfsfu234/form-validationNo rewrite, no component migration. It attaches to markup you've already shipped.
Built on top of native HTML validation. The library reads required, type, pattern, minlength, maxlength, min, max, step, and other standard attributes before applying any custom rules.
Register every form on your website with configureForms(), then initialize only the forms on the current page using autoInit(). Perfect for multi-page applications.
Validate uploads beyond what HTML can do. Restrict file types, image dimensions, file size, number of files, MIME types, and more—all before upload.
Validate inputs, textareas, selects, checkboxes, radio groups, files and custom configurations using one consistent API.
Display inline errors, target your own DOM elements, or disable built-in rendering completely and integrate with your own UI.
No third-party runtime packages. Smaller bundles, fewer supply chain concerns, easier upgrades, and complete control over your application.
Version 3 introduces configuration-driven validation, automatic form registration, generated API documentation, stronger TypeScript support and a cleaner developer experience from installation to deployment.
Register every form once and keep all validation rules in one place.
Automatically initialize only the forms that exist on the current page.
Both validate() and submit() return promises for cleaner async code.
Ships with full typings and generated API documentation.
Every field on the right is plain HTML — required, type="email", minlength="10". No JavaScript was written for this demo beyond mounting the library.
Every NFSFU234 library solves a specific frontend problem while remaining lightweight, dependency-free where possible, and designed to work well alongside the rest of the ecosystem.
HTML-first form validation with configuration-driven rules, AJAX submission, automatic form initialization, file validation, and first-class TypeScript support.
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