Fieldwork — Form Validation & Enhancement (Vanilla JS)

Fieldwork is a small, dependency-free form validation & enhancement library in vanilla JavaScript. Add data-rules to your inputs and Fieldwork validates them on blur and submit, renders accessible inline error messages, wires the ARIA for you, and can handle async submission — no framework, no build step.

Highlights

• Declarative: data-rules="required|email|minlength:8"; 14 built-in rules.
• Accessible by default: aria-invalid, aria-describedby, focus management, role=alert.
• Validate on blur + submit; live re-validation after the first error.
• Custom rules & messages; honors native constraint attributes.
• Events + optional async submit (fetch JSON) with server-error display.
• Zero dependencies, no build step, ES modules; CSS-variable theming.