CodePen Embed - :optional Seçici

<input type="text"/>
<input type="text" required/>

input {
   display:block;
   margin-bottom: 10px;
}
input:optional {
  background:red;
}

This Pen is owned by W3TR on CodePen.

This Pen doesn't use any external CSS resources.

This Pen doesn't use any external JavaScript resources.