Untitled

<html>
<head>
<script type="text/javascript">
(function() {
class MyBlink extends HTMLElement {
  constructor() {
    super();
    this._speed = 250;
  }
  connectedCallback() {
	if(this.hasAttribute('speed')) {
		this._speed = this.getAttribute('speed');
	}
	this.style.visibility = 'hidden';
	let that = this;
	window.setInterval(function() {
		that.style.visibility = (that.style.visibility === 'visible') ?  'hidden' : 'visible';
	}, this._speed);
  }
}
customElements.define('my-blink', MyBlink);
})();
</script>
</head>
<body>
	<my-blink speed="1000">Text to blink here</my-blink>
</body>
</html>