fade in fade out w3schools code example

Example 1: css fade in

/* Just add .fade-in class to element */

.fade-in {
	animation: fadeIn 2s;
  	opacity: 1;
}

@keyframes fadeIn {
  from {
  	opacity: 0;
  }
  to {
 	opacity: 1;
  }
}

Example 2: animation fade in css

document.getElementById("test").children[0].className += " load";