JSFiddle - React, Tailwind, and code Playground

by rafalry

HTML

<form>
    <input type="text" name="website" pattern="[A-Z0-9]{5}"/>
    <input type="submit"/>
    </form>

CSS

input:required:invalid, input:focus:invalid {
    background-color:red;
  }
  input:required:valid {
    background-color:green;
  }