Add real-time validation to a signup form with no JavaScript

Every time someone leaves a required field blank on my signup form, it just submits anyway.

Beginner to intermediateRead 4 minDoing: under an hour6 steps

▶ Start

What you'll have at the end

A signup form that blocks submission and shows a clear message for a blank field, a bad email, and a short password.

Before you start

You need

A signup form with one input each for a name, an email, and a password, none of them yet carrying a required, type, or length attribute.

Not covered

Enforcing password strength beyond length, such as mixed case or symbols, or confirming the email address is real: both need a script or a server round trip.

Leans on

6 steps

Where to go next

This page renders fine; validation still fails

go there instead when validation means your markup fails an HTML validator; this recipe is about a visitor leaving a field wrong, a different meaning of the same word.

Checked 20 Aug 2026

Part of the HTML cookbook