Autohide

by Lazaro Contreras

HTML

<div></div>

CSS

div{
  position:absolute;
  display:block;
  width:100px;
  height:100px;
  background:red;
  transition: 1s all;
}
div.hide{
  opacity: 0;
}

JavaScript

var c = document.querySelector('div');
let t
c.onmousemove = function(e){
  c.classList.remove('hide')
  clearTimeout(t)
  t = setTimeout(function(){
  	c.classList.add('hide')
  }, 3000);
}