CSS pulsing

Taken from example: https://codepen.io/wifeo/pen/KwdXwV

HTML

<div class="container">
  
</div>

<button onClick="add()">
Remove
</button>

CSS

body {
  background: fff;
}


.container {
  width:250px;
  height:75px;
  -webkit-border-radius: 5px;
	-moz-border-radius: 5px;
	border-radius: 5px;
	float:left;
	background-color: #90b6d5;
  -webkit-animation: pulse 0.40s 2 ease ;
  animation: pulse 0.50s 2 ease ;
}

@-webkit-keyframes pulse {to {box-shadow: 0px 0px 15px 6px rgba(0,0,0,0.21);}}
@keyframes pulse {to {box-shadow: 0px 0px 15px 6px rgba(0,0,0,0.21);}}

JavaScript

function add(){
	alert('0');

}