:out-of-range

The :out-of-range pseudo selector in CSS matches input elements when their value is outside the range specified as being acceptable.

<input type="number" min="5" max="10">

input:out-of-range {
  border: 5px solid red;
}

I believe it’s only relevant on input[type=number]. Range inputs don’t allow values outside their min/max and it doesn’t make much sense on any other type of input. Perhaps text-y inputs with a maxlength, but the behavior on those in most browsers is to prevent entry past the max anyway.

More Info

• :in-range

Browser Support