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                <form action="#">
  <input id="text" minlength="3" maxlength="5" />
  <input type="submit"/>


                input:invalid {
  color: red;
  animation: invalid 0.001s;

@keyframes invalid {
  0%: {
    outline-color: #000;


                // Normally you would have to manually call the native validation API directly or wait for a submit to catch an invalid event:

text.addEventListener('invalid', function(e){

// But if you use Selector Listeners - a hack based on animation event listeners - you can handle an invalid state immediately at the time of entry:

document.addEventListener('animationstart', function(e){
  if (e.animationName == "invalid") console.log(e);