Weird Use Of JavaScript Vibrate API

I was updating my hosts.eladkarako.com with some new spam sites,
during the process I’ve notices some weird *native* JavaScript API using, as part of pop-up and alert the page was also “sending vibrations” apparently to make the page more reliable,

navigator.vibrate = navigator.vibrate || navigator.webkitVibrate || navigator.mozVibrate || navigator.msVibrate;
navigator.vibrate([1000, 500, 1000, 500, 1000, 500, 1000, 500, 1000]);

weird but effecting hardware using JavaScript, and native programming- is always kind’a cool,