Answers for "setTimeout trong JS W3Schools"

javascript settimeout

setTimeout(function(){
 	alert("Sup!"); 
}, 2000);//wait 2 seconds

how to set timeout for a div tag in html

<script>
  const timeout = document.getElementsByClassName('classname')
  setTimeout(hideElement, 1000) //milliseconds until timeout//
  function hideElement() {
    timeout.style.display = 'none'
</script>
<div class="classname">
  <span> &times; </span>