html/forms/form-validation/min-max.html

<!DOCTYPE html>
<html lang="en-US">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <title>Minimum and maximum examples</title>
    <style>
      input:invalid {
        border: 2px dashed red;
      }

      input:valid {
        border: 2px solid black;
      }
    </style>
  </head>

<body>
    <form>
      <p>
        <label for="n1">How old are you?</label>
        <input type="number" id="n1" name="age" pattern="\d+" min="12" max="120">
      </p>
      <p>
        <label for="t3">Leave a short message</label>
        <textarea id="t3" name="msg" rows="5" maxlength="10"></textarea>
      </p>
      <p>
        <button>Submit</button>
      </p>
    </form>
</body>

</html>