4 digit length inputs

by Joe

HTML

<!-- begin snippet: js hide: false console: false babel: null -->

<!-- language: lang-css -->

    input:valid {
      color: green;
    }
    input:invalid {
      color: red;
    }

<!-- language: lang-html -->

    <form name="form1"> 
     <input type="text"  name="pincode" maxlength="4"  id="pin" pattern="\d{4}" required/>
     <input type="Submit"/> 
    </form>

<!-- end snippet -->

CSS

input:valid {
      color: green;
    }
    input:invalid {
      color: red;
    }